NEW - bug 229487: [api] manage task list structure internally

https://bugs.eclipse.org/bugs/show_bug.cgi?id=229487

138 files changed, 934 insertions, 831 deletions

diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AbstractTaskListFilter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AbstractTaskListFilter.java
index 800dd25ee..68c6e1169 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AbstractTaskListFilter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AbstractTaskListFilter.java
@@ -10,9 +10,9 @@ package org.eclipse.mylyn.internal.tasks.ui;
 import java.util.Collection;
 
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * Custom filters are used so that the "Find:" filter can 'see through' any filters that may have been applied.
@@ -29,23 +29,23 @@ public abstract class AbstractTaskListFilter {
 	 * 
 	 * TODO: Move to an internal utility class
 	 */
-	public static boolean hasDescendantIncoming(AbstractTaskContainer container) {
+	public static boolean hasDescendantIncoming(ITaskElement container) {
 		return hasDescendantIncoming(container, ITasksCoreConstants.MAX_SUBTASK_DEPTH);
 	}
 
-	public static boolean hasIncompleteDescendant(AbstractTaskContainer container) {
+	public static boolean hasIncompleteDescendant(ITaskElement container) {
 		return hasIncompleteDescendant(container, ITasksCoreConstants.MAX_SUBTASK_DEPTH);
 	}
 
-	private static boolean hasDescendantIncoming(AbstractTaskContainer container, int depth) {
-		Collection<AbstractTask> children = container.getChildren();
+	private static boolean hasDescendantIncoming(ITaskElement container, int depth) {
+		Collection<ITask> children = container.getChildren();
 		if (children == null || depth <= 0) {
 			return false;
 		}
 
-		for (AbstractTask task : children) {
+		for (ITask task : children) {
 			if (task != null) {
-				AbstractTask containedRepositoryTask = task;
+				ITask containedRepositoryTask = task;
 				if (containedRepositoryTask.getSynchronizationState() == SynchronizationState.INCOMING) {
 					return true;
 				} else if (TasksUiPlugin.getDefault().groupSubtasks(container)
@@ -57,15 +57,15 @@ public abstract class AbstractTaskListFilter {
 		return false;
 	}
 
-	private static boolean hasIncompleteDescendant(AbstractTaskContainer container, int depth) {
-		Collection<AbstractTask> children = container.getChildren();
+	private static boolean hasIncompleteDescendant(ITaskElement container, int depth) {
+		Collection<ITask> children = container.getChildren();
 		if (children == null || depth <= 0) {
 			return false;
 		}
 
-		for (AbstractTask task : children) {
+		for (ITask task : children) {
 			if (task != null) {
-				AbstractTask containedRepositoryTask = task;
+				ITask containedRepositoryTask = task;
 				if (!containedRepositoryTask.isCompleted()) {
 					return true;
 				} else if (hasIncompleteDescendant(task, depth - 1)) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AddExistingTaskJob.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AddExistingTaskJob.java
index 5b708ea70..10ed6ef73 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AddExistingTaskJob.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AddExistingTaskJob.java
@@ -18,12 +18,12 @@ import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.StructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AttachmentUtil.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AttachmentUtil.java
index 51e49f86f..ce6e9aaec 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AttachmentUtil.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/AttachmentUtil.java
@@ -24,17 +24,17 @@ import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.tasks.core.TaskDataStorageManager;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.core.data.FileTaskAttachmentSource;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractAttachmentHandler;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.FileAttachment;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryAttachment;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskAttachment;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskAttachmentHandler;
 import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
 
@@ -58,7 +58,7 @@ public class AttachmentUtil {
 	 */
 	@Deprecated
 	public static boolean attachContext(AbstractAttachmentHandler attachmentHandler, TaskRepository repository,
-			AbstractTask task, String longComment, IProgressMonitor monitor) throws CoreException {
+			ITask task, String longComment, IProgressMonitor monitor) throws CoreException {
 		ContextCore.getContextManager().saveContext(task.getHandleIdentifier());
 		final File sourceContextFile = ContextCore.getContextManager().getFileForContext(task.getHandleIdentifier());
 
@@ -86,7 +86,7 @@ public class AttachmentUtil {
 	}
 
 	public static boolean postContext(AbstractRepositoryConnector connector, TaskRepository repository,
-			AbstractTask task, String comment, IProgressMonitor monitor) throws CoreException {
+			ITask task, String comment, IProgressMonitor monitor) throws CoreException {
 		AbstractTaskAttachmentHandler attachmentHandler = connector.getTaskAttachmentHandler();
 		ContextCore.getContextManager().saveContext(task.getHandleIdentifier());
 		File file = ContextCore.getContextManager().getFileForContext(task.getHandleIdentifier());
@@ -106,7 +106,7 @@ public class AttachmentUtil {
 	 * 
 	 * @return an empty set if no contexts
 	 */
-	public static Set<RepositoryAttachment> getContextAttachments(TaskRepository repository, AbstractTask task) {
+	public static Set<RepositoryAttachment> getContextAttachments(TaskRepository repository, ITask task) {
 		TaskDataStorageManager taskDataManager = TasksUiPlugin.getTaskDataStorageManager();
 		Set<RepositoryAttachment> contextAttachments = new HashSet<RepositoryAttachment>();
 		if (taskDataManager != null) {
@@ -124,7 +124,7 @@ public class AttachmentUtil {
 		return contextAttachments;
 	}
 
-	public static boolean hasContext(TaskRepository repository, AbstractTask task) {
+	public static boolean hasContext(TaskRepository repository, ITask task) {
 		if (repository == null || task == null) {
 			return false;
 		} else {
@@ -151,7 +151,7 @@ public class AttachmentUtil {
 	 */
 	@Deprecated
 	public static boolean retrieveContext(AbstractAttachmentHandler attachmentHandler, TaskRepository repository,
-			AbstractTask task, RepositoryAttachment attachment, String destinationPath, IProgressMonitor monitor)
+			ITask task, RepositoryAttachment attachment, String destinationPath, IProgressMonitor monitor)
 			throws CoreException {
 
 		File destinationContextFile = ContextCore.getContextManager().getFileForContext(task.getHandleIdentifier());
@@ -183,7 +183,7 @@ public class AttachmentUtil {
 	}
 
 	public static boolean getContext(AbstractRepositoryConnector connector, TaskRepository repository,
-			AbstractTask task, TaskAttribute attribute, IProgressMonitor monitor) throws CoreException {
+			ITask task, TaskAttribute attribute, IProgressMonitor monitor) throws CoreException {
 		AbstractTaskAttachmentHandler attachmentHandler = connector.getTaskAttachmentHandler();
 		File file = ContextCore.getContextManager().getFileForContext(task.getHandleIdentifier());
 		try {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/IDynamicSubMenuContributor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/IDynamicSubMenuContributor.java
index 9545835f3..1ce4ca9f7 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/IDynamicSubMenuContributor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/IDynamicSubMenuContributor.java
@@ -10,13 +10,13 @@ package org.eclipse.mylyn.internal.tasks.ui;
 import java.util.List;
 
 import org.eclipse.jface.action.MenuManager;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Mik Kersten
  */
 public interface IDynamicSubMenuContributor {
 
-	public abstract MenuManager getSubMenuManager(List<AbstractTaskContainer> selectedElements);
+	public abstract MenuManager getSubMenuManager(List<ITaskElement> selectedElements);
 
 }
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ITaskHighlighter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ITaskHighlighter.java
index f1d1def5e..930f4ded0 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ITaskHighlighter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ITaskHighlighter.java
@@ -8,7 +8,7 @@
 
 package org.eclipse.mylyn.internal.tasks.ui;
 
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.graphics.Color;
 
 /**
@@ -16,5 +16,5 @@ import org.eclipse.swt.graphics.Color;
  */
 public interface ITaskHighlighter {
 
-	public Color getHighlightColor(AbstractTask task);
+	public Color getHighlightColor(ITask task);
 }
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/LocalTaskConnectorUi.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/LocalTaskConnectorUi.java
index b304459c3..c8cac253b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/LocalTaskConnectorUi.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/LocalTaskConnectorUi.java
@@ -10,11 +10,11 @@ package org.eclipse.mylyn.internal.tasks.ui;
 
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.wizard.IWizard;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.LocalRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskSelection;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewLocalTaskWizard;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.mylyn.tasks.ui.wizards.AbstractRepositorySettingsPage;
@@ -26,7 +26,7 @@ import org.eclipse.mylyn.tasks.ui.wizards.AbstractRepositorySettingsPage;
 public class LocalTaskConnectorUi extends AbstractRepositoryConnectorUi {
 
 	@Override
-	public ImageDescriptor getTaskKindOverlay(AbstractTask task) {
+	public ImageDescriptor getTaskKindOverlay(ITask task) {
 		return super.getTaskKindOverlay(task);
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MarkTaskMenuContributor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MarkTaskMenuContributor.java
index 7d3e62011..844e5e385 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MarkTaskMenuContributor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MarkTaskMenuContributor.java
@@ -18,8 +18,8 @@ import org.eclipse.mylyn.internal.tasks.ui.actions.MarkTaskCompleteAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.MarkTaskIncompleteAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.MarkTaskReadAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.MarkTaskUnreadAction;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Rob Elves
@@ -28,12 +28,12 @@ public class MarkTaskMenuContributor implements IDynamicSubMenuContributor {
 
 	private static final String LABEL = "Mark as";
 
-	public MenuManager getSubMenuManager(final List<AbstractTaskContainer> selectedElements) {
+	public MenuManager getSubMenuManager(final List<ITaskElement> selectedElements) {
 		final MenuManager subMenuManager = new MenuManager(LABEL);
-		AbstractTask singleTask = null;
+		ITask singleTask = null;
 		if (selectedElements.size() == 1) {
-			if (selectedElements.get(0) instanceof AbstractTask) {
-				singleTask = (AbstractTask) selectedElements.get(0);
+			if (selectedElements.get(0) instanceof ITask) {
+				singleTask = (ITask) selectedElements.get(0);
 			}
 		}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MoveToCategoryMenuContributor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MoveToCategoryMenuContributor.java
index a67e27296..33e18aaf3 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MoveToCategoryMenuContributor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/MoveToCategoryMenuContributor.java
@@ -16,11 +16,12 @@ import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.action.MenuManager;
 import org.eclipse.jface.action.Separator;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.actions.NewCategoryAction;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
 /**
@@ -31,13 +32,13 @@ public class MoveToCategoryMenuContributor implements IDynamicSubMenuContributor
 
 	private static final String LABEL = "Move to";
 
-	public MenuManager getSubMenuManager(final List<AbstractTaskContainer> selectedElements) {
+	public MenuManager getSubMenuManager(final List<ITaskElement> selectedElements) {
 		final MenuManager subMenuManager = new MenuManager(LABEL);
 
 		// Compute selected tasks
 		List<AbstractTask> selectedTasks = new ArrayList<AbstractTask>(selectedElements.size());
-		for (AbstractTaskContainer element : selectedElements) {
-			if (element instanceof AbstractTask) {
+		for (ITaskElement element : selectedElements) {
+			if (element instanceof ITask) {
 				selectedTasks.add((AbstractTask) element);
 			}
 		}
@@ -106,9 +107,9 @@ public class MoveToCategoryMenuContributor implements IDynamicSubMenuContributor
 	 * @param selectedElements
 	 * @param category
 	 */
-	private void moveToCategory(final List<AbstractTaskContainer> selectedElements, AbstractTaskCategory category) {
-		for (AbstractTaskContainer element : selectedElements) {
-			if (element instanceof AbstractTask) {
+	private void moveToCategory(final List<ITaskElement> selectedElements, AbstractTaskCategory category) {
+		for (ITaskElement element : selectedElements) {
+			if (element instanceof ITask) {
 				TasksUi.getTaskList().addTask((AbstractTask) element, category);
 			}
 		}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/OpenRepositoryTaskJob.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/OpenRepositoryTaskJob.java
index 6b2b8ff83..faab15c13 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/OpenRepositoryTaskJob.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/OpenRepositoryTaskJob.java
@@ -14,11 +14,11 @@ import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractTaskDataHandler;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/PersonProposalProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/PersonProposalProvider.java
index c09fb516d..cb51c9406 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/PersonProposalProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/PersonProposalProvider.java
@@ -20,10 +20,11 @@ import org.eclipse.jface.fieldassist.IContentProposal;
 import org.eclipse.jface.fieldassist.IContentProposalProvider;
 import org.eclipse.mylyn.commons.net.AuthenticationCredentials;
 import org.eclipse.mylyn.commons.net.AuthenticationType;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryAttachment;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskComment;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
@@ -160,7 +161,7 @@ public class PersonProposalProvider implements IContentProposalProvider {
 				}
 			}
 
-			for (AbstractTask task : tasks) {
+			for (ITask task : tasks) {
 				addAddresses(task, addressSet);
 			}
 		}
@@ -168,7 +169,7 @@ public class PersonProposalProvider implements IContentProposalProvider {
 		return addressSet;
 	}
 
-	private void addAddresses(AbstractTask task, Set<String> addressSet) {
+	private void addAddresses(ITask task, Set<String> addressSet) {
 		// TODO: Creator, and CC should be stored on AbstractTask
 
 		addAddress(task.getOwner(), addressSet);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/RefactorRepositoryUrlOperation.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/RefactorRepositoryUrlOperation.java
index 683b468cf..31bebf551 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/RefactorRepositoryUrlOperation.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/RefactorRepositoryUrlOperation.java
@@ -28,7 +28,7 @@ import org.eclipse.mylyn.internal.tasks.core.TaskDataStorageManager;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskAttribute;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.monitor.core.InteractionEvent;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * @author Rob Elves
@@ -101,9 +101,9 @@ public class RefactorRepositoryUrlOperation extends TaskListModifyOperation {
 
 	private void refactorOfflineHandles(String oldRepositoryUrl, String newRepositoryUrl) {
 		TaskDataStorageManager taskDataManager = TasksUiPlugin.getTaskDataStorageManager();
-		for (AbstractTask task : getTaskList().getAllTasks()) {
+		for (ITask task : getTaskList().getAllTasks()) {
 			if (task != null) {
-				AbstractTask repositoryTask = task;
+				ITask repositoryTask = task;
 				if (repositoryTask.getRepositoryUrl().equals(oldRepositoryUrl)) {
 					RepositoryTaskData newTaskData = taskDataManager.getNewTaskData(repositoryTask.getRepositoryUrl(),
 							repositoryTask.getTaskId());
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleDatePicker.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleDatePicker.java
index 7d0c05ea6..7f9660831 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleDatePicker.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleDatePicker.java
@@ -18,10 +18,11 @@ import java.util.List;
 
 import org.eclipse.jface.action.MenuManager;
 import org.eclipse.mylyn.internal.provisional.commons.ui.DatePicker;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
@@ -49,7 +50,7 @@ public class ScheduleDatePicker extends Composite {
 
 	private final String initialText = DatePicker.LABEL_CHOOSE;
 
-	private final List<AbstractTaskContainer> tasks;
+	private final List<ITaskElement> tasks;
 
 	private final ScheduleTaskMenuContributor contributor;
 
@@ -59,7 +60,7 @@ public class ScheduleDatePicker extends Composite {
 
 	private ScheduledTaskContainer scheduledContainer;
 
-	public ScheduleDatePicker(Composite parent, AbstractTask task, int style) {
+	public ScheduleDatePicker(Composite parent, ITask task, int style) {
 		super(parent, style);
 		if (task != null) {
 			if (task.getScheduledForDate() != null) {
@@ -75,7 +76,7 @@ public class ScheduleDatePicker extends Composite {
 		contributor = new ScheduleTaskMenuContributor() {
 
 			@Override
-			protected Date getScheduledForDate(AbstractTask singleTaskSelection) {
+			protected Date getScheduledForDate(ITask singleTaskSelection) {
 				return ScheduleDatePicker.this.scheduledDate;
 			}
 
@@ -99,7 +100,7 @@ public class ScheduleDatePicker extends Composite {
 				notifyPickerListeners();
 			}
 		};
-		tasks = new ArrayList<AbstractTaskContainer>();
+		tasks = new ArrayList<ITaskElement>();
 		tasks.add(task);
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleTaskMenuContributor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleTaskMenuContributor.java
index 0a014c81e..4454a02e7 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleTaskMenuContributor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/ScheduleTaskMenuContributor.java
@@ -21,10 +21,11 @@ import org.eclipse.jface.window.Window;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.provisional.commons.ui.DatePicker;
 import org.eclipse.mylyn.internal.provisional.commons.ui.DateSelectionDialog;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.ui.PlatformUI;
 
 /**
@@ -43,21 +44,21 @@ public class ScheduleTaskMenuContributor implements IDynamicSubMenuContributor {
 
 	private AbstractTask singleTaskSelection;
 
-	private final List<AbstractTaskContainer> taskListElementsToSchedule = new ArrayList<AbstractTaskContainer>();
+	private final List<ITaskElement> taskListElementsToSchedule = new ArrayList<ITaskElement>();
 
-	public MenuManager getSubMenuManager(final List<AbstractTaskContainer> selectedElements) {
+	public MenuManager getSubMenuManager(final List<ITaskElement> selectedElements) {
 
 		final MenuManager subMenuManager = new MenuManager(LABEL_REMINDER);
 
 		if (selectedElements.size() == 1) {
-			AbstractTaskContainer selectedElement = selectedElements.get(0);
-			if (selectedElement instanceof AbstractTask) {
+			ITaskElement selectedElement = selectedElements.get(0);
+			if (selectedElement instanceof ITask) {
 				singleTaskSelection = (AbstractTask) selectedElement;
 			}
 		}
 
-		for (AbstractTaskContainer selectedElement : selectedElements) {
-			if (selectedElement instanceof AbstractTask) {
+		for (ITaskElement selectedElement : selectedElements) {
+			if (selectedElement instanceof ITask) {
 				taskListElementsToSchedule.add(selectedElement);
 			}
 		}
@@ -196,7 +197,7 @@ public class ScheduleTaskMenuContributor implements IDynamicSubMenuContributor {
 	private boolean canSchedule() {
 		if (taskListElementsToSchedule.size() == 0) {
 			return true;
-		} else if (singleTaskSelection instanceof AbstractTask) {
+		} else if (singleTaskSelection instanceof ITask) {
 			return ((!(singleTaskSelection).isCompleted()) || taskListElementsToSchedule.size() > 0);
 		} else {
 			return taskListElementsToSchedule.size() > 0;
@@ -215,7 +216,7 @@ public class ScheduleTaskMenuContributor implements IDynamicSubMenuContributor {
 //	}
 
 	protected void setScheduledDate(ScheduledTaskContainer dateContainer) {
-		for (AbstractTaskContainer element : taskListElementsToSchedule) {
+		for (ITaskElement element : taskListElementsToSchedule) {
 			AbstractTask task = getTaskForElement(element, true);
 			if (dateContainer != null && dateContainer.getStart() != null) {
 				TasksUiPlugin.getTaskActivityManager().setScheduledFor(task, dateContainer.getStart().getTime(),
@@ -226,7 +227,7 @@ public class ScheduleTaskMenuContributor implements IDynamicSubMenuContributor {
 		}
 	}
 
-	protected Date getScheduledForDate(final AbstractTask singleTaskSelection) {
+	protected Date getScheduledForDate(final ITask singleTaskSelection) {
 		if (singleTaskSelection != null) {
 			return singleTaskSelection.getScheduledForDate();
 		}
@@ -237,14 +238,14 @@ public class ScheduleTaskMenuContributor implements IDynamicSubMenuContributor {
 		return task.internalIsFloatingScheduledDate();
 	}
 
-	private boolean isPastReminder(AbstractTask task) {
+	private boolean isPastReminder(ITask task) {
 		Date date = getScheduledForDate(task);
 		return TasksUiPlugin.getTaskActivityManager().isPastReminder(date, task.isCompleted());
 	}
 
-	private AbstractTask getTaskForElement(AbstractTaskContainer element, boolean force) {
+	private AbstractTask getTaskForElement(ITaskElement element, boolean force) {
 		AbstractTask task = null;
-		if (element instanceof AbstractTask) {
+		if (element instanceof ITask) {
 			task = (AbstractTask) element;
 		}
 		return task;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskActivityMonitor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskActivityMonitor.java
index 7c6ab445a..d99261d2f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskActivityMonitor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskActivityMonitor.java
@@ -19,11 +19,12 @@ import org.eclipse.mylyn.context.core.IInteractionContext;
 import org.eclipse.mylyn.context.core.IInteractionContextListener;
 import org.eclipse.mylyn.context.core.IInteractionContextManager;
 import org.eclipse.mylyn.context.core.IInteractionElement;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityManager;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.monitor.core.InteractionEvent;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * Monitors task activity and maintains task activation history
@@ -119,7 +120,7 @@ public class TaskActivityMonitor {
 						return true;
 					}
 				} else if (event.getDelta().equals("removed")) {
-					AbstractTask task = taskList.getTask(event.getStructureHandle());
+					ITask task = taskList.getTask(event.getStructureHandle());
 					if (task != null) {
 						taskActivityManager.removeElapsedTime(task, event.getDate(), event.getEndDate());
 						return true;
@@ -152,7 +153,7 @@ public class TaskActivityMonitor {
 	/**
 	 * Returns the task corresponding to the interaction event history item at the specified position
 	 */
-	protected AbstractTask getHistoryTaskAt(int pos) {
+	protected ITask getHistoryTaskAt(int pos) {
 		InteractionEvent event = ContextCore.getContextManager().getActivityMetaContext().getInteractionHistory().get(
 				pos);
 		if (event.getDelta().equals(IInteractionContextManager.ACTIVITY_DELTA_ACTIVATED)) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskCompletionFilter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskCompletionFilter.java
index c794317c0..7c46f8b2f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskCompletionFilter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskCompletionFilter.java
@@ -7,7 +7,7 @@
  *******************************************************************************/
 package org.eclipse.mylyn.internal.tasks.ui;
 
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * @author Mik Kersten
@@ -16,8 +16,8 @@ public class TaskCompletionFilter extends AbstractTaskListFilter {
 
 	@Override
 	public boolean select(Object parent, Object element) {
-		if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask task = (ITask) element;
 			return !task.isCompleted();
 		}
 		return true;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryDropDown.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryDropDown.java
index b1fb55e68..938c2ad49 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryDropDown.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryDropDown.java
@@ -20,13 +20,14 @@ import org.eclipse.jface.action.ActionContributionItem;
 import org.eclipse.jface.action.IContributionItem;
 import org.eclipse.jface.action.Separator;
 import org.eclipse.jface.resource.ImageDescriptor;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivationHistory;
 import org.eclipse.mylyn.internal.tasks.ui.actions.ActivateTaskDialogAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskActivateAction;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskElementLabelProvider;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.ui.IWorkingSet;
@@ -77,7 +78,7 @@ public class TaskHistoryDropDown extends CompoundContributionItem {
 
 		@Override
 		public void run() {
-			AbstractTask active = TasksUi.getTaskActivityManager().getActiveTask();
+			ITask active = TasksUi.getTaskActivityManager().getActiveTask();
 			if (active != null) {
 				TasksUi.getTaskActivityManager().deactivateTask(active);
 			}
@@ -144,17 +145,17 @@ public class TaskHistoryDropDown extends CompoundContributionItem {
 		List<AbstractTask> tasks = new ArrayList<AbstractTask>(taskHistory.getPreviousTasks());
 		Set<IWorkingSet> sets = TaskListView.getActiveWorkingSets();
 		if (scopedToWorkingSet && !sets.isEmpty()) {
-			Set<AbstractTask> allWorkingSetTasks = new HashSet<AbstractTask>();
+			Set<ITask> allWorkingSetTasks = new HashSet<ITask>();
 			for (IWorkingSet workingSet : sets) {
 				IAdaptable[] elements = workingSet.getElements();
 				for (IAdaptable adaptable : elements) {
-					if (adaptable instanceof AbstractTaskContainer) {
-						allWorkingSetTasks.addAll(((AbstractTaskContainer) adaptable).getChildren());
+					if (adaptable instanceof ITaskElement) {
+						allWorkingSetTasks.addAll(((ITaskElement) adaptable).getChildren());
 					}
 				}
 			}
 			List<AbstractTask> allScopedTasks = new ArrayList<AbstractTask>(tasks);
-			for (AbstractTask task : tasks) {
+			for (ITask task : tasks) {
 				if (!allWorkingSetTasks.contains(task)) {
 					allScopedTasks.remove(task);
 				}
@@ -180,7 +181,7 @@ public class TaskHistoryDropDown extends CompoundContributionItem {
 		Separator separator = new Separator();
 		items.add(separator);
 
-		AbstractTask active = TasksUi.getTaskActivityManager().getActiveTask();
+		ITask active = TasksUi.getTaskActivityManager().getActiveTask();
 		if (active != null) {
 			IContributionItem pauseContributionItem = new CommandContributionItem(PlatformUI.getWorkbench(),
 					"org.eclipse.mylyn.ui.context.capture.pause", // id 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryHandler.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryHandler.java
index 7f58b66cf..bd8d1a82e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryHandler.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskHistoryHandler.java
@@ -17,10 +17,10 @@ import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.core.runtime.SafeRunner;
 import org.eclipse.jface.util.SafeRunnable;
 import org.eclipse.mylyn.context.core.ContextCore;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivationHistory;
 import org.eclipse.mylyn.internal.tasks.ui.actions.ActivateTaskDialogAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskActivateAction;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.commands.ICommandService;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskJobFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskJobFactory.java
index b875db0a1..3f0659bf6 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskJobFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskJobFactory.java
@@ -16,6 +16,7 @@ import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.core.runtime.jobs.Job;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.ITaskJobFactory;
 import org.eclipse.mylyn.internal.tasks.core.ITaskListRunnable;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
@@ -26,8 +27,7 @@ import org.eclipse.mylyn.internal.tasks.core.sync.SynchronizeQueriesJob;
 import org.eclipse.mylyn.internal.tasks.core.sync.SynchronizeRepositoriesJob;
 import org.eclipse.mylyn.internal.tasks.core.sync.SynchronizeTasksJob;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskRepositoryManager;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskAttachmentSource;
@@ -56,7 +56,7 @@ public class TaskJobFactory implements ITaskJobFactory {
 		this.repositoryManager = repositoryManager;
 	}
 
-	public SynchronizationJob createSynchronizeTasksJob(AbstractRepositoryConnector connector, Set<AbstractTask> tasks) {
+	public SynchronizationJob createSynchronizeTasksJob(AbstractRepositoryConnector connector, Set<ITask> tasks) {
 		SynchronizeAllTasksJob job = new SynchronizeAllTasksJob(taskList, taskDataManager, repositoryManager,
 				connector, tasks);
 		job.setProperty(IProgressConstants.ICON_PROPERTY, TasksUiImages.REPOSITORY_SYNCHRONIZE);
@@ -65,7 +65,7 @@ public class TaskJobFactory implements ITaskJobFactory {
 	}
 
 	public SynchronizationJob createSynchronizeTasksJob(AbstractRepositoryConnector connector,
-			TaskRepository taskRepository, Set<AbstractTask> tasks) {
+			TaskRepository taskRepository, Set<ITask> tasks) {
 		SynchronizeTasksJob job = new SynchronizeTasksJob(taskList, taskDataManager, connector, taskRepository, tasks);
 		job.setProperty(IProgressConstants.ICON_PROPERTY, TasksUiImages.REPOSITORY_SYNCHRONIZE);
 		job.setPriority(Job.LONG);
@@ -89,7 +89,7 @@ public class TaskJobFactory implements ITaskJobFactory {
 	}
 
 	public SubmitJob createSubmitTaskJob(AbstractRepositoryConnector connector, TaskRepository taskRepository,
-			final AbstractTask task, TaskData taskData, Set<TaskAttribute> changedAttributes) {
+			final ITask task, TaskData taskData, Set<TaskAttribute> changedAttributes) {
 		SubmitJob job = new SubmitTaskJob(taskDataManager, connector, taskRepository, task, taskData, changedAttributes);
 		job.setPriority(Job.INTERACTIVE);
 		try {
@@ -140,8 +140,8 @@ public class TaskJobFactory implements ITaskJobFactory {
 	}
 
 	public SubmitJob createSubmitTaskAttachmentJob(AbstractRepositoryConnector connector,
-			TaskRepository taskRepository, final AbstractTask task, AbstractTaskAttachmentSource source,
-			String comment, TaskAttribute attachmentAttribute) {
+			TaskRepository taskRepository, final ITask task, AbstractTaskAttachmentSource source, String comment,
+			TaskAttribute attachmentAttribute) {
 		SubmitJob job = new SubmitTaskAttachmentJob(taskDataManager, connector, taskRepository, task, source, comment,
 				attachmentAttribute);
 		job.setPriority(Job.INTERACTIVE);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskLabelDecorator.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskLabelDecorator.java
index 41e7f9a0c..144e6c994 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskLabelDecorator.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskLabelDecorator.java
@@ -16,9 +16,9 @@ import org.eclipse.jface.viewers.IDecoration;
 import org.eclipse.jface.viewers.ILabelProviderListener;
 import org.eclipse.jface.viewers.ILightweightLabelDecorator;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskElementLabelProvider;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
@@ -51,8 +51,8 @@ public class TaskLabelDecorator implements ILightweightLabelDecorator {
 					decoration.addSuffix("   [" + taskRepository.getRepositoryLabel() + "]");
 				}
 			}
-		} else if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		} else if (element instanceof ITask) {
+			ITask task = (ITask) element;
 			if (!task.isCompleted()
 					&& (TasksUiPlugin.getTaskActivityManager().isDueToday(task) || TasksUiPlugin.getTaskActivityManager()
 							.isOverdue(task))) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListBackupManager.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListBackupManager.java
index 35989e798..58cd289d1 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListBackupManager.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListBackupManager.java
@@ -34,10 +34,10 @@ import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.util.IPropertyChangeListener;
 import org.eclipse.jface.util.PropertyChangeEvent;
 import org.eclipse.mylyn.internal.context.core.ContextPreferenceContstants;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
 import org.eclipse.mylyn.internal.tasks.ui.util.TaskDataExportOperation;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.progress.IProgressService;
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListHyperlink.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListHyperlink.java
index c6ebf24b8..878f3b957 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListHyperlink.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListHyperlink.java
@@ -9,7 +9,7 @@
 package org.eclipse.mylyn.internal.tasks.ui;
 
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonColors;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.MouseEvent;
 import org.eclipse.swt.events.MouseTrackListener;
@@ -46,7 +46,7 @@ public class TaskListHyperlink extends ImageHyperlink {
 
 	private boolean strikeThrough;
 
-	private AbstractTask task;
+	private ITask task;
 
 	public TaskListHyperlink(Composite parent, int style) {
 		super(parent, style);
@@ -60,7 +60,7 @@ public class TaskListHyperlink extends ImageHyperlink {
 		super.dispose();
 	}
 
-	public AbstractTask getTask() {
+	public ITask getTask() {
 		return task;
 	}
 
@@ -86,7 +86,7 @@ public class TaskListHyperlink extends ImageHyperlink {
 		this.strikeThrough = strikethrough;
 	}
 
-	public void setTask(AbstractTask task) {
+	public void setTask(ITask task) {
 		this.task = task;
 		if (task != null) {
 			if ((getStyle() & SWT.SHORT) != 0) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListManager.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListManager.java
index ede92d94f..51526d71a 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListManager.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskListManager.java
@@ -22,6 +22,8 @@ import java.util.regex.Pattern;
 
 import org.eclipse.core.runtime.Platform;
 import org.eclipse.mylyn.internal.context.core.ContextCorePlugin;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.LocalRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
@@ -32,8 +34,7 @@ import org.eclipse.mylyn.internal.tasks.core.externalization.TaskListExternalize
 import org.eclipse.mylyn.internal.tasks.ui.util.TaskListElementImporter;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskActivityListener;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
@@ -230,7 +231,7 @@ public class TaskListManager {
 	 * @deprecated
 	 */
 	@Deprecated
-	public AbstractTask getActiveTask() {
+	public ITask getActiveTask() {
 		return TasksUi.getTaskActivityManager().getActiveTask();
 	}
 
@@ -280,7 +281,7 @@ public class TaskListManager {
 	 * @deprecated
 	 */
 	@Deprecated
-	public void deactivateTask(AbstractTask task) {
+	public void deactivateTask(ITask task) {
 		TasksUi.getTaskActivityManager().deactivateTask(task);
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskPriorityFilter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskPriorityFilter.java
index 9fc6518fd..55652f43d 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskPriorityFilter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskPriorityFilter.java
@@ -7,9 +7,9 @@
  *******************************************************************************/
 package org.eclipse.mylyn.internal.tasks.ui;
 
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Mik Kersten
@@ -31,12 +31,12 @@ public class TaskPriorityFilter extends AbstractTaskListFilter {
 
 	@Override
 	public boolean select(Object parent, Object element) {
-		if (element instanceof AbstractTaskContainer) {
-			String priority = ((AbstractTaskContainer) element).getPriority();
+		if (element instanceof ITaskElement) {
+			String priority = ((ITaskElement) element).getPriority();
 			if (priority == null || !(priority.startsWith(PRIORITY_PREFIX))) {
 				return true;
 			}
-			if (priorityLevel.compareTo(((AbstractTaskContainer) element).getPriority()) >= 0) {
+			if (priorityLevel.compareTo(((ITaskElement) element).getPriority()) >= 0) {
 				return true;
 			}
 			return false;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskSearchPage.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskSearchPage.java
index 004d674a4..4bee24308 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskSearchPage.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskSearchPage.java
@@ -19,11 +19,11 @@ import org.eclipse.jface.layout.GridDataFactory;
 import org.eclipse.jface.wizard.WizardPage;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.TaskRepositoryManager;
 import org.eclipse.mylyn.internal.tasks.ui.search.SearchHitCollector;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTransfer.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTransfer.java
index 71b60a848..c564ddfc1 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTransfer.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTransfer.java
@@ -14,7 +14,7 @@ import java.io.DataInputStream;
 import java.io.DataOutputStream;
 import java.io.IOException;
 
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.dnd.ByteArrayTransfer;
 import org.eclipse.swt.dnd.TransferData;
 
@@ -50,11 +50,11 @@ public class TaskTransfer extends ByteArrayTransfer {
 
 	@Override
 	protected void javaToNative(Object data, TransferData transferData) {
-		if (!(data instanceof AbstractTask[])) {
+		if (!(data instanceof ITask[])) {
 			return;
 		}
 
-		AbstractTask[] tasks = (AbstractTask[]) data;
+		ITask[] tasks = (ITask[]) data;
 		int resourceCount = tasks.length;
 
 		try {
@@ -65,7 +65,7 @@ public class TaskTransfer extends ByteArrayTransfer {
 			dataOut.writeInt(resourceCount);
 
 			// write each resource
-			for (AbstractTask task : tasks) {
+			for (ITask task : tasks) {
 				writeTask(dataOut, task);
 			}
 
@@ -88,7 +88,7 @@ public class TaskTransfer extends ByteArrayTransfer {
 		DataInputStream in = new DataInputStream(new ByteArrayInputStream(bytes));
 		try {
 			int count = in.readInt();
-			AbstractTask[] results = new AbstractTask[count];
+			ITask[] results = new ITask[count];
 			for (int i = 0; i < count; i++) {
 				results[i] = readTask(in);
 			}
@@ -98,12 +98,12 @@ public class TaskTransfer extends ByteArrayTransfer {
 		}
 	}
 
-	private AbstractTask readTask(DataInputStream dataIn) throws IOException {
+	private ITask readTask(DataInputStream dataIn) throws IOException {
 		String handle = dataIn.readUTF();
 		return TasksUiPlugin.getTaskListManager().getTaskList().getTask(handle);
 	}
 
-	private void writeTask(DataOutputStream dataOut, AbstractTask task) throws IOException {
+	private void writeTask(DataOutputStream dataOut, ITask task) throws IOException {
 		dataOut.writeUTF(task.getHandleIdentifier());
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTrimWidget.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTrimWidget.java
index ffe1c8aee..60e10c8cf 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTrimWidget.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskTrimWidget.java
@@ -30,9 +30,9 @@ import org.eclipse.mylyn.internal.tasks.ui.actions.TaskActivateAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskDeactivateAction;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskActivityListener;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.TaskActivityAdapter;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.SWT;
@@ -68,7 +68,7 @@ public class TaskTrimWidget extends WorkbenchWindowControlContribution {
 
 	private Composite composite = null;
 
-	private AbstractTask activeTask = null;
+	private ITask activeTask = null;
 
 	private MenuManager menuManager = null;
 
@@ -85,13 +85,13 @@ public class TaskTrimWidget extends WorkbenchWindowControlContribution {
 	private final ITaskActivityListener TASK_ACTIVITY_LISTENER = new TaskActivityAdapter() {
 
 		@Override
-		public void taskActivated(AbstractTask task) {
+		public void taskActivated(ITask task) {
 			activeTask = task;
 			indicateActiveTask();
 		}
 
 		@Override
-		public void taskDeactivated(AbstractTask task) {
+		public void taskDeactivated(ITask task) {
 			activeTask = null;
 			indicateNoActiveTask();
 		}
@@ -283,7 +283,7 @@ public class TaskTrimWidget extends WorkbenchWindowControlContribution {
 			for (String menuPath : TasksUiPlugin.getDefault().getDynamicMenuMap().keySet()) {
 				for (IDynamicSubMenuContributor contributor : TasksUiPlugin.getDefault().getDynamicMenuMap().get(
 						menuPath)) {
-					List<AbstractTaskContainer> selectedElements = new ArrayList<AbstractTaskContainer>();
+					List<ITaskElement> selectedElements = new ArrayList<ITaskElement>();
 					selectedElements.add(activeTask);
 					MenuManager subMenuManager = contributor.getSubMenuManager(selectedElements);
 					if (subMenuManager != null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskWorkingSetFilter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskWorkingSetFilter.java
index 432351718..c0768d9a6 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskWorkingSetFilter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TaskWorkingSetFilter.java
@@ -12,8 +12,8 @@ import java.util.Arrays;
 import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.ui.IWorkingSet;
 
 /**
@@ -29,7 +29,7 @@ public class TaskWorkingSetFilter extends AbstractTaskListFilter {
 
 	@Override
 	public boolean select(Object parent, Object element) {
-		if (parent instanceof AbstractTask) {
+		if (parent instanceof ITask) {
 			return true;
 		}
 
@@ -37,19 +37,19 @@ public class TaskWorkingSetFilter extends AbstractTaskListFilter {
 			return true;
 		}
 
-		if (parent == null && element instanceof AbstractTaskContainer) {
-			return isContainedInWorkingSet((AbstractTaskContainer) element);
+		if (parent == null && element instanceof ITaskElement) {
+			return isContainedInWorkingSet((ITaskElement) element);
 		}
-		if (parent instanceof AbstractTaskContainer && !(parent instanceof ScheduledTaskContainer)) {
-			return isContainedInWorkingSet((AbstractTaskContainer) parent);
+		if (parent instanceof ITaskElement && !(parent instanceof ScheduledTaskContainer)) {
+			return isContainedInWorkingSet((ITaskElement) parent);
 		}
 		if (element instanceof LocalTask) {
-			for (AbstractTaskContainer container : ((LocalTask) element).getParentContainers()) {
+			for (ITaskElement container : ((LocalTask) element).getParentContainers()) {
 				return isContainedInWorkingSet(container);
 			}
 		}
-		if (parent instanceof ScheduledTaskContainer && element instanceof AbstractTask) {
-			for (AbstractTaskContainer query : ((AbstractTask) element).getParentContainers()) {
+		if (parent instanceof ScheduledTaskContainer && element instanceof ITask) {
+			for (ITaskElement query : ((ITask) element).getParentContainers()) {
 				if (isContainedInWorkingSet(query)) {
 					return true;
 				}
@@ -59,7 +59,7 @@ public class TaskWorkingSetFilter extends AbstractTaskListFilter {
 		return true;
 	}
 
-	private boolean isContainedInWorkingSet(AbstractTaskContainer container) {
+	private boolean isContainedInWorkingSet(ITaskElement container) {
 		if (elements == null) {
 			return true;
 		}
@@ -67,9 +67,9 @@ public class TaskWorkingSetFilter extends AbstractTaskListFilter {
 		boolean seenTaskWorkingSets = false;
 		String handleIdentifier = container.getHandleIdentifier();
 		for (IAdaptable adaptable : elements) {
-			if (adaptable instanceof AbstractTaskContainer) {
+			if (adaptable instanceof ITaskElement) {
 				seenTaskWorkingSets = true;
-				if (handleIdentifier.equals(((AbstractTaskContainer) adaptable).getHandleIdentifier())) {
+				if (handleIdentifier.equals(((ITaskElement) adaptable).getHandleIdentifier())) {
 					return true;
 				}
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksReminderDialog.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksReminderDialog.java
index 298af9bac..21e49f387 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksReminderDialog.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksReminderDialog.java
@@ -19,7 +19,8 @@ import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerSorter;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
@@ -150,14 +151,14 @@ public class TasksReminderDialog extends Dialog {
 	@Override
 	protected void buttonPressed(int buttonId) {
 		if (buttonId == DISMISS_ALL_ID) {
-			for (AbstractTask t : tasks) {
+			for (ITask t : tasks) {
 				t.setReminded(true);
 			}
 			okPressed();
 		} else if (buttonId == DISMISS_ID) {
 			Object sel = ((IStructuredSelection) tableViewer.getSelection()).getFirstElement();
-			if (sel != null && sel instanceof AbstractTask) {
-				AbstractTask t = (AbstractTask) sel;
+			if (sel != null && sel instanceof ITask) {
+				ITask t = (ITask) sel;
 				t.setReminded(true);
 				tasks.remove(t);
 				if (tasks.isEmpty()) {
@@ -168,8 +169,8 @@ public class TasksReminderDialog extends Dialog {
 			}
 		} else if (buttonId == SNOOZE_ID) {
 			Object sel = ((IStructuredSelection) tableViewer.getSelection()).getFirstElement();
-			if (sel != null && sel instanceof AbstractTask) {
-				AbstractTask t = (AbstractTask) sel;
+			if (sel != null && sel instanceof ITask) {
+				ITask t = (ITask) sel;
 				t.setReminded(false);
 				t.setScheduledForDate(new Date(new Date().getTime() + DAY));
 				tasks.remove(t);
@@ -202,8 +203,8 @@ public class TasksReminderDialog extends Dialog {
 		}
 
 		public String getColumnText(Object element, int columnIndex) {
-			if (element instanceof AbstractTask) {
-				AbstractTask task = (AbstractTask) element;
+			if (element instanceof ITask) {
+				ITask task = (ITask) element;
 				switch (columnIndex) {
 				case 0:
 					return task.getSummary();
@@ -235,8 +236,8 @@ public class TasksReminderDialog extends Dialog {
 
 		@Override
 		public int compare(Viewer viewer, Object obj1, Object obj2) {
-			AbstractTask t1 = (AbstractTask) obj1;
-			AbstractTask t2 = (AbstractTask) obj2;
+			ITask t1 = (ITask) obj1;
+			ITask t2 = (ITask) obj2;
 
 			switch (criteria) {
 			case DESCRIPTION:
@@ -250,15 +251,15 @@ public class TasksReminderDialog extends Dialog {
 			}
 		}
 
-		private int compareDescription(AbstractTask task1, AbstractTask task2) {
+		private int compareDescription(ITask task1, ITask task2) {
 			return task1.getSummary().compareToIgnoreCase(task2.getSummary());
 		}
 
-		private int comparePriority(AbstractTask task1, AbstractTask task2) {
+		private int comparePriority(ITask task1, ITask task2) {
 			return task1.getPriority().compareTo(task2.getPriority());
 		}
 
-		private int compareDate(AbstractTask task1, AbstractTask task2) {
+		private int compareDate(ITask task1, ITask task2) {
 			return task2.getScheduledForDate().compareTo(task1.getScheduledForDate());
 		}
 	}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiImages.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiImages.java
index 7f07df33b..53d929097 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiImages.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiImages.java
@@ -14,7 +14,7 @@ import java.net.URL;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.resource.ImageRegistry;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.graphics.Image;
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiPlugin.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiPlugin.java
index b4fc5ae97..9cffa5a5c 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiPlugin.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/TasksUiPlugin.java
@@ -53,6 +53,8 @@ import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.context.core.ContextPreferenceContstants;
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotification;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonColors;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.LocalRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.RepositoryTemplateManager;
@@ -60,6 +62,8 @@ import org.eclipse.mylyn.internal.tasks.core.TaskActivityManager;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
 import org.eclipse.mylyn.internal.tasks.core.TaskDataStorageManager;
 import org.eclipse.mylyn.internal.tasks.core.TaskRepositoryManager;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.core.data.TaskDataManager;
 import org.eclipse.mylyn.internal.tasks.core.data.TaskDataStore;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractAttributeFactory;
@@ -77,15 +81,12 @@ import org.eclipse.mylyn.internal.tasks.ui.notifications.TaskListNotificationRem
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiExtensionReader;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskRepositoriesView;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskActivityListener;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.RepositoryTemplate;
 import org.eclipse.mylyn.tasks.core.TaskActivityAdapter;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.mylyn.tasks.ui.AbstractTaskRepositoryLinkProvider;
 import org.eclipse.mylyn.tasks.ui.editors.AbstractTaskEditorFactory;
@@ -251,12 +252,12 @@ public class TasksUiPlugin extends AbstractUIPlugin {
 	private static ITaskActivityListener CONTEXT_TASK_ACTIVITY_LISTENER = new TaskActivityAdapter() {
 
 		@Override
-		public void taskActivated(final AbstractTask task) {
+		public void taskActivated(final ITask task) {
 			ContextCore.getContextManager().activateContext(task.getHandleIdentifier());
 		}
 
 		@Override
-		public void taskDeactivated(final AbstractTask task) {
+		public void taskDeactivated(final ITask task) {
 			ContextCore.getContextManager().deactivateContext(task.getHandleIdentifier());
 		}
 
@@ -287,7 +288,7 @@ public class TasksUiPlugin extends AbstractUIPlugin {
 						repository.getConnectorKind());
 				AbstractRepositoryConnectorUi connectorUi = getConnectorUi(repository.getConnectorKind());
 				if (connectorUi != null && !connectorUi.isCustomNotificationHandling()) {
-					for (AbstractTask repositoryTask : TasksUiPlugin.getTaskListManager().getTaskList().getTasks(
+					for (ITask repositoryTask : TasksUiPlugin.getTaskListManager().getTaskList().getTasks(
 							repository.getRepositoryUrl())) {
 						if ((repositoryTask.getLastReadTimeStamp() == null || repositoryTask.getSynchronizationState() == SynchronizationState.INCOMING)
 								&& repositoryTask.isNotified() == false) {
@@ -303,7 +304,7 @@ public class TasksUiPlugin extends AbstractUIPlugin {
 			for (AbstractRepositoryQuery query : TasksUiPlugin.getTaskListManager().getTaskList().getQueries()) {
 				AbstractRepositoryConnectorUi connectorUi = getConnectorUi(query.getConnectorKind());
 				if (!connectorUi.isCustomNotificationHandling()) {
-					for (AbstractTask hit : query.getChildren()) {
+					for (ITask hit : query.getChildren()) {
 						if (hit.isNotified() == false) {
 							notifications.add(new TaskListNotificationQueryIncoming(hit));
 							hit.setNotified(true);
@@ -815,12 +816,12 @@ public class TasksUiPlugin extends AbstractUIPlugin {
 		return INSTANCE;
 	}
 
-	public boolean groupSubtasks(AbstractTaskContainer container) {
+	public boolean groupSubtasks(ITaskElement container) {
 		boolean groupSubtasks = TasksUiPlugin.getDefault().getPreferenceStore().getBoolean(
 				TasksUiPreferenceConstants.GROUP_SUBTASKS);
 
-		if (container instanceof AbstractTask) {
-			AbstractRepositoryConnectorUi connectorUi = TasksUiPlugin.getConnectorUi(((AbstractTask) container).getConnectorKind());
+		if (container instanceof ITask) {
+			AbstractRepositoryConnectorUi connectorUi = TasksUiPlugin.getConnectorUi(((ITask) container).getConnectorKind());
 			if (connectorUi != null) {
 				if (connectorUi.forceSubtaskHierarchy()) {
 					groupSubtasks = true;
@@ -1124,7 +1125,7 @@ public class TasksUiPlugin extends AbstractUIPlugin {
 	 */
 	@SuppressWarnings("restriction")
 	@Deprecated
-	public TaskListNotification getIncommingNotification(AbstractRepositoryConnector connector, AbstractTask task) {
+	public TaskListNotification getIncommingNotification(AbstractRepositoryConnector connector, ITask task) {
 
 		TaskListNotification notification = new TaskListNotification(task);
 		RepositoryTaskData newTaskData = getTaskDataStorageManager().getNewTaskData(task.getRepositoryUrl(),
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractChangeCompletionAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractChangeCompletionAction.java
index b4efee317..2d5c61a35 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractChangeCompletionAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractChangeCompletionAction.java
@@ -11,21 +11,22 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 import java.util.List;
 
 import org.eclipse.jface.action.Action;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Mik Kersten
  */
 public class AbstractChangeCompletionAction extends Action {
 
-	protected boolean shouldEnable(List<AbstractTaskContainer> selectedElements) {
+	protected boolean shouldEnable(List<ITaskElement> selectedElements) {
 		boolean allLocalTasks = true;
-		for (AbstractTaskContainer abstractTaskContainer : selectedElements) {
-			if (!(abstractTaskContainer instanceof AbstractTask)) {
+		for (ITaskElement abstractTaskContainer : selectedElements) {
+			if (!(abstractTaskContainer instanceof ITask)) {
 				allLocalTasks = false;
 				break;
-			} else if (!((AbstractTask) abstractTaskContainer).isLocal()) {
+			} else if (!((ITask) abstractTaskContainer).isLocal()) {
 				allLocalTasks = false;
 				break;
 			}
@@ -36,7 +37,7 @@ public class AbstractChangeCompletionAction extends Action {
 	protected String generateMessage(List<AbstractTask> toComplete, String status) {
 		String message = "Mark selected local tasks " + status + "?\n\n";
 		int i = 0;
-		for (AbstractTask task : toComplete) {
+		for (ITask task : toComplete) {
 			i++;
 			if (i < 20) {
 				message += "    ";
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskAction.java
index df74bcdb0..cdb5ae738 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskAction.java
@@ -11,33 +11,35 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 import java.util.List;
 
 import org.eclipse.jface.action.Action;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Rob Elves
  */
 public abstract class AbstractTaskAction extends Action {
 
-	protected List<AbstractTaskContainer> selectedElements;
+	protected List<ITaskElement> selectedElements;
 
 	@Override
 	public void run() {
-		for (AbstractTaskContainer element : selectedElements) {
-			if (element instanceof AbstractTask) {
+		for (ITaskElement element : selectedElements) {
+			if (element instanceof ITask) {
 				AbstractTask repositoryTask = (AbstractTask) element;
 				performActionOnTask(repositoryTask);
 			} else if (element instanceof AbstractRepositoryQuery) {
 				AbstractRepositoryQuery repositoryQuery = (AbstractRepositoryQuery) element;
-				for (AbstractTask queryHit : repositoryQuery.getChildren()) {
+				for (ITask queryHit : repositoryQuery.getChildren()) {
 					performActionOnTask(queryHit);
 				}
 			} else if (element != null) {
-				AbstractTaskContainer container = element;
-				for (AbstractTask iTask : container.getChildren()) {
+				ITaskElement container = element;
+				for (ITask iTask : container.getChildren()) {
 					if (iTask != null) {
-						AbstractTask repositoryTask = iTask;
+						ITask repositoryTask = iTask;
 						performActionOnTask(repositoryTask);
 					}
 				}
@@ -45,7 +47,7 @@ public abstract class AbstractTaskAction extends Action {
 		}
 	}
 
-	protected abstract void performActionOnTask(AbstractTask repositoryTask);
+	protected abstract void performActionOnTask(ITask repositoryTask);
 
 	protected boolean containsArchiveContainer(List<AbstractTaskContainer> selectedElements) {
 		return false;//selectedElements.contains(TasksUiPlugin.getTaskListManager().getTaskList().getArchiveContainer());
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskEditorAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskEditorAction.java
index 72bdb4dbd..de08582bb 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskEditorAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskEditorAction.java
@@ -9,8 +9,8 @@
 package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.dialogs.MessageDialog;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.actions.BaseSelectionListenerAction;
@@ -30,7 +30,7 @@ public abstract class AbstractTaskEditorAction extends BaseSelectionListenerActi
 		this.editor = taskEditor;
 	}
 
-	protected boolean taskDirty(AbstractTask task) {
+	protected boolean taskDirty(ITask task) {
 		return (((editor != null && editor.isDirty())
 				|| task.getSynchronizationState().equals(SynchronizationState.OUTGOING) || task.getSynchronizationState()
 				.equals(SynchronizationState.CONFLICT)));
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskRepositoryAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskRepositoryAction.java
index 6b48afbc9..c835c8054 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskRepositoryAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AbstractTaskRepositoryAction.java
@@ -9,8 +9,8 @@
 package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.actions.BaseSelectionListenerAction;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskDialogAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskDialogAction.java
index 2d5779f13..6a21acc87 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskDialogAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskDialogAction.java
@@ -10,8 +10,9 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.window.Window;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.IWorkbenchWindowActionDelegate;
@@ -40,7 +41,7 @@ public class ActivateTaskDialogAction extends ActionDelegate implements IWorkben
 		}
 
 		Object result = dlg.getFirstResult();
-		if (result instanceof AbstractTask) {
+		if (result instanceof ITask) {
 			AbstractTask task = (AbstractTask) result;
 			TasksUi.getTaskActivityManager().activateTask(task);
 //			manager.getTaskActivationHistory().addTask(task);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskHistoryDropDownAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskHistoryDropDownAction.java
index 7861b8877..21dbc7d52 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskHistoryDropDownAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ActivateTaskHistoryDropDownAction.java
@@ -11,12 +11,12 @@ import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.action.IMenuCreator;
 import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivationHistory;
 import org.eclipse.mylyn.internal.tasks.ui.TaskHistoryDropDown;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Menu;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachAction.java
index fd53e6dba..14d4bb33e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachAction.java
@@ -9,11 +9,12 @@
 package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractAttachmentHandler;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizard;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizardDialog;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.ISharedImages;
@@ -43,8 +44,8 @@ public class AttachAction extends AbstractTaskEditorAction {
 			editor.showBusy(true);
 		}
 		Object selection = this.getStructuredSelection().getFirstElement();
-		if (selection instanceof AbstractTask) {
-			if (taskDirty((AbstractTask) selection)) {
+		if (selection instanceof ITask) {
+			if (taskDirty((ITask) selection)) {
 				openInformationDialog(LABEL, "Submit changes or synchronize task before adding attachments.");
 				return;
 			}
@@ -74,8 +75,8 @@ public class AttachAction extends AbstractTaskEditorAction {
 
 	@Override
 	protected boolean updateSelection(IStructuredSelection selection) {
-		if (selection.getFirstElement() instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) selection.getFirstElement();
+		if (selection.getFirstElement() instanceof ITask) {
+			ITask task = (ITask) selection.getFirstElement();
 			TaskRepository repository = TasksUi.getRepositoryManager().getRepository(task.getConnectorKind(),
 					task.getRepositoryUrl());
 			if (repository != null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachScreenshotAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachScreenshotAction.java
index e7822d415..185be8e71 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachScreenshotAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/AttachScreenshotAction.java
@@ -9,9 +9,10 @@
 package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizard;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizardDialog;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.PlatformUI;
@@ -35,8 +36,8 @@ public class AttachScreenshotAction extends AttachAction {
 			editor.showBusy(true);
 		}
 		Object selection = super.getStructuredSelection().getFirstElement();
-		if (selection instanceof AbstractTask) {
-			if (taskDirty((AbstractTask) selection)) {
+		if (selection instanceof ITask) {
+			if (taskDirty((ITask) selection)) {
 				openInformationDialog(LABEL, "Submit changes or synchronize task before adding attachments.");
 				return;
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ClearOutgoingAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ClearOutgoingAction.java
index 8c8259e63..0e16f7895 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ClearOutgoingAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ClearOutgoingAction.java
@@ -15,11 +15,12 @@ import org.eclipse.core.runtime.CoreException;
 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * Discard outgoing changes on selected task TODO: Enable multi task discard?
@@ -32,23 +33,23 @@ public class ClearOutgoingAction extends Action {
 
 	public static final String ID = "org.eclipse.mylyn.tasklist.actions.mark.discard";
 
-	private final List<AbstractTaskContainer> selectedElements;
+	private final List<ITaskElement> selectedElements;
 
-	public ClearOutgoingAction(List<AbstractTaskContainer> selectedElements) {
+	public ClearOutgoingAction(List<ITaskElement> selectedElements) {
 		this.selectedElements = selectedElements;
 		setText(ACTION_NAME);
 		setToolTipText(ACTION_NAME);
 		setImageDescriptor(CommonImages.CLEAR);
 		setId(ID);
-		if (selectedElements.size() == 1 && (selectedElements.get(0) instanceof AbstractTask)) {
-			AbstractTask task = (AbstractTask) selectedElements.get(0);
+		if (selectedElements.size() == 1 && (selectedElements.get(0) instanceof ITask)) {
+			ITask task = (ITask) selectedElements.get(0);
 			setEnabled(hasOutgoingChanges(task));
 		} else {
 			setEnabled(false);
 		}
 	}
 
-	private boolean hasOutgoingChanges(AbstractTask task) {
+	private boolean hasOutgoingChanges(ITask task) {
 		return task.getSynchronizationState().equals(SynchronizationState.OUTGOING)
 				|| task.getSynchronizationState().equals(SynchronizationState.CONFLICT);
 	}
@@ -57,7 +58,7 @@ public class ClearOutgoingAction extends Action {
 	public void run() {
 		ArrayList<AbstractTask> toClear = new ArrayList<AbstractTask>();
 		for (Object selectedObject : selectedElements) {
-			if (selectedObject instanceof AbstractTask && hasOutgoingChanges((AbstractTask) selectedObject)) {
+			if (selectedObject instanceof ITask && hasOutgoingChanges((ITask) selectedObject)) {
 				toClear.add(((AbstractTask) selectedObject));
 			}
 		}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CloneTaskAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CloneTaskAction.java
index c8fb5d413..b8949d28e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CloneTaskAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CloneTaskAction.java
@@ -19,7 +19,7 @@ import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskSelection;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Shell;
@@ -62,8 +62,8 @@ public class CloneTaskAction extends BaseSelectionListenerAction implements IVie
 	public void run() {
 		try {
 			for (Object selectedObject : getStructuredSelection().toList()) {
-				if (selectedObject instanceof AbstractTask) {
-					AbstractTask task = (AbstractTask) selectedObject;
+				if (selectedObject instanceof ITask) {
+					ITask task = (ITask) selectedObject;
 
 					String description = "Cloned from: " + CopyTaskDetailsAction.getTextForTask(task);
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CopyTaskDetailsAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CopyTaskDetailsAction.java
index fafa7271f..e0547f97f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CopyTaskDetailsAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/CopyTaskDetailsAction.java
@@ -10,12 +10,13 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.ui.editors.RepositoryTaskSelection;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.dnd.Clipboard;
 import org.eclipse.swt.dnd.TextTransfer;
@@ -60,7 +61,7 @@ public class CopyTaskDetailsAction extends BaseSelectionListenerAction {
 	// API 3.0: move to TasksUiUtil / into core
 	public static String getTextForTask(Object object) {
 		String text = "";
-		if (object instanceof AbstractTask) {
+		if (object instanceof ITask) {
 			AbstractTask task = (AbstractTask) object;
 			if (task.getTaskKey() != null) {
 				text += task.getTaskKey() + ": ";
@@ -86,8 +87,8 @@ public class CopyTaskDetailsAction extends BaseSelectionListenerAction {
 			AbstractRepositoryQuery query = (AbstractRepositoryQuery) object;
 			text += query.getSummary();
 			text += "\n" + query.getUrl();
-		} else if (object instanceof AbstractTaskContainer) {
-			AbstractTaskContainer element = (AbstractTaskContainer) object;
+		} else if (object instanceof ITaskElement) {
+			ITaskElement element = (ITaskElement) object;
 			text = element.getSummary();
 		} else if (object instanceof RepositoryTaskSelection) {
 			RepositoryTaskSelection selection = (RepositoryTaskSelection) object;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteAction.java
index 1ea7a1469..e182a0cbc 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteAction.java
@@ -15,12 +15,13 @@ import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.context.core.ContextCore;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.ui.ISharedImages;
@@ -58,8 +59,8 @@ public class DeleteAction extends Action {
 			i++;
 			if (i < 20) {
 				// TODO this action should be based on the action enablement and check if the container is user managed or not
-				if (object instanceof AbstractTaskContainer) {
-					elements += "    " + ((AbstractTaskContainer) object).getSummary() + "\n";
+				if (object instanceof ITaskElement) {
+					elements += "    " + ((ITaskElement) object).getSummary() + "\n";
 				}
 			} else {
 				elements += "...";
@@ -71,8 +72,8 @@ public class DeleteAction extends Action {
 
 		if (toDelete.size() == 1) {
 			Object object = toDelete.get(0);
-			if (object instanceof AbstractTask) {
-				if (((AbstractTask) object).isLocal()) {
+			if (object instanceof ITask) {
+				if (((ITask) object).isLocal()) {
 					message = "Permanently delete the task listed below?";
 				} else {
 					message = "Delete the planning information and context for the repository task?  The server"
@@ -100,7 +101,7 @@ public class DeleteAction extends Action {
 		}
 
 		for (Object selectedObject : toDelete) {
-			if (selectedObject instanceof AbstractTask) {
+			if (selectedObject instanceof ITask) {
 				AbstractTask task = null;
 				task = (AbstractTask) selectedObject;
 				TasksUi.getTaskActivityManager().deactivateTask(task);
@@ -124,7 +125,7 @@ public class DeleteAction extends Action {
 				// if (!deleteConfirmed)
 				// return;
 				TaskCategory cat = (TaskCategory) selectedObject;
-				for (AbstractTask task : cat.getChildren()) {
+				for (ITask task : cat.getChildren()) {
 					ContextCore.getContextManager().deleteContext(task.getHandleIdentifier());
 					TasksUiUtil.closeEditorInActivePage(task, false);
 				}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteTaskRepositoryAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteTaskRepositoryAction.java
index 77315bfae..d58699e72 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteTaskRepositoryAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/DeleteTaskRepositoryAction.java
@@ -17,9 +17,9 @@ import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.ui.TaskRepositoryUtil;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.ISharedImages;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/GoToUnreadTaskAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/GoToUnreadTaskAction.java
index 7a7f97ce6..146bb945c 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/GoToUnreadTaskAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/GoToUnreadTaskAction.java
@@ -14,12 +14,12 @@ import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.TreePath;
 import org.eclipse.jface.viewers.TreeSelection;
 import org.eclipse.jface.viewers.TreeViewer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker;
 import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker.Direction;
 import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker.TreeVisitor;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.widgets.Tree;
 import org.eclipse.swt.widgets.TreeItem;
 import org.eclipse.ui.IViewActionDelegate;
@@ -55,8 +55,8 @@ public class GoToUnreadTaskAction extends Action implements IViewActionDelegate,
 		TreeVisitor visitor = new TreeVisitor() {
 			@Override
 			public boolean visit(Object object) {
-				if (object instanceof AbstractTask) {
-					AbstractTask task = (AbstractTask) object;
+				if (object instanceof ITask) {
+					ITask task = (ITask) object;
 					if (task.getSynchronizationState() == SynchronizationState.INCOMING) {
 						return true;
 					}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskCompleteAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskCompleteAction.java
index e49bde314..ff2ae9287 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskCompleteAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskCompleteAction.java
@@ -13,9 +13,10 @@ import java.util.Date;
 import java.util.List;
 
 import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.PlatformUI;
@@ -30,9 +31,9 @@ public class MarkTaskCompleteAction extends AbstractChangeCompletionAction {
 
 	private static final String ACTION_NAME = "Complete";
 
-	private final List<AbstractTaskContainer> selectedElements;
+	private final List<ITaskElement> selectedElements;
 
-	public MarkTaskCompleteAction(List<AbstractTaskContainer> selectedElements) {
+	public MarkTaskCompleteAction(List<ITaskElement> selectedElements) {
 		this.selectedElements = selectedElements;
 		setText(ACTION_NAME);
 		setToolTipText("Mark " + ACTION_NAME);
@@ -49,7 +50,7 @@ public class MarkTaskCompleteAction extends AbstractChangeCompletionAction {
 	public void run() {
 		List<AbstractTask> toComplete = new ArrayList<AbstractTask>();
 		for (Object selectedObject : selectedElements) {
-			if (selectedObject instanceof AbstractTask) {
+			if (selectedObject instanceof ITask) {
 				AbstractTask task = (AbstractTask) selectedObject;
 				if (task.isLocal()) {
 					toComplete.add(task);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskIncompleteAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskIncompleteAction.java
index fcae1491c..fa11ef29e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskIncompleteAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskIncompleteAction.java
@@ -12,9 +12,10 @@ import java.util.ArrayList;
 import java.util.List;
 
 import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.PlatformUI;
@@ -30,9 +31,9 @@ public class MarkTaskIncompleteAction extends AbstractChangeCompletionAction {
 
 	public static final String ID = "org.eclipse.mylyn.tasklist.actions.mark.incomplete";
 
-	private final List<AbstractTaskContainer> selectedElements;
+	private final List<ITaskElement> selectedElements;
 
-	public MarkTaskIncompleteAction(List<AbstractTaskContainer> selectedElements) {
+	public MarkTaskIncompleteAction(List<ITaskElement> selectedElements) {
 		this.selectedElements = selectedElements;
 		setText(ACTION_NAME);
 		setToolTipText("Mark " + ACTION_NAME);
@@ -46,7 +47,7 @@ public class MarkTaskIncompleteAction extends AbstractChangeCompletionAction {
 	public void run() {
 		List<AbstractTask> toComplete = new ArrayList<AbstractTask>();
 		for (Object selectedObject : selectedElements) {
-			if (selectedObject instanceof AbstractTask) {
+			if (selectedObject instanceof ITask) {
 				AbstractTask task = (AbstractTask) selectedObject;
 				if (task.isLocal()) {
 					toComplete.add(task);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskReadAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskReadAction.java
index ac3e6b048..2f5f0b8f9 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskReadAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskReadAction.java
@@ -12,8 +12,8 @@ import java.util.List;
 
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Rob Elves
@@ -26,7 +26,7 @@ public class MarkTaskReadAction extends AbstractTaskAction {
 
 	public static final String DEFINITION_ID = "org.eclipse.mylyn.tasks.ui.command.markTaskRead";
 
-	public MarkTaskReadAction(List<AbstractTaskContainer> selectedElements) {
+	public MarkTaskReadAction(List<ITaskElement> selectedElements) {
 		super.selectedElements = selectedElements;
 		setText(ACTION_NAME);
 		setToolTipText("Mark " + ACTION_NAME);
@@ -36,8 +36,8 @@ public class MarkTaskReadAction extends AbstractTaskAction {
 //			setEnabled(false);
 //		} else {
 		setEnabled(selectedElements.size() > 0);
-		if (selectedElements.size() == 1 && (selectedElements.get(0) instanceof AbstractTask)) {
-			AbstractTask task = (AbstractTask) selectedElements.get(0);
+		if (selectedElements.size() == 1 && (selectedElements.get(0) instanceof ITask)) {
+			ITaskElement task = selectedElements.get(0);
 			setEnabled(!(task instanceof LocalTask));
 		} else {
 			setEnabled(true);
@@ -46,7 +46,7 @@ public class MarkTaskReadAction extends AbstractTaskAction {
 	}
 
 	@Override
-	protected void performActionOnTask(AbstractTask repositoryTask) {
+	protected void performActionOnTask(ITask repositoryTask) {
 		TasksUiPlugin.getTaskDataManager().setTaskRead(repositoryTask, true);
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskUnreadAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskUnreadAction.java
index 0d4e803b1..44bd0d33d 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskUnreadAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/MarkTaskUnreadAction.java
@@ -12,8 +12,8 @@ import java.util.List;
 
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Rob Elves
@@ -26,7 +26,7 @@ public class MarkTaskUnreadAction extends AbstractTaskAction {
 
 	public static final String DEFINITION_ID = "org.eclipse.mylyn.tasks.ui.command.markTaskUnread";
 
-	public MarkTaskUnreadAction(List<AbstractTaskContainer> selectedElements) {
+	public MarkTaskUnreadAction(List<ITaskElement> selectedElements) {
 		this.selectedElements = selectedElements;
 		setText(ACTION_NAME);
 		setToolTipText(ACTION_NAME);
@@ -37,8 +37,8 @@ public class MarkTaskUnreadAction extends AbstractTaskAction {
 //		if (containsArchiveContainer(selectedElements)) {
 //			setEnabled(false);
 //		} else {
-		if (selectedElements.size() == 1 && (selectedElements.get(0) instanceof AbstractTask)) {
-			AbstractTask task = (AbstractTask) selectedElements.get(0);
+		if (selectedElements.size() == 1 && (selectedElements.get(0) instanceof ITask)) {
+			ITask task = (ITask) selectedElements.get(0);
 			setEnabled(!task.isLocal());
 		} else {
 			setEnabled(true);
@@ -47,7 +47,7 @@ public class MarkTaskUnreadAction extends AbstractTaskAction {
 	}
 
 	@Override
-	protected void performActionOnTask(AbstractTask repositoryTask) {
+	protected void performActionOnTask(ITask repositoryTask) {
 		TasksUiPlugin.getTaskDataManager().setTaskRead(repositoryTask, false);
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewCategoryAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewCategoryAction.java
index f1da4c691..02b7d2d7b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewCategoryAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewCategoryAction.java
@@ -16,11 +16,11 @@ import org.eclipse.jface.dialogs.InputDialog;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.window.Window;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IViewActionDelegate;
 import org.eclipse.ui.IViewPart;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewSubTaskAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewSubTaskAction.java
index a708d2d01..900909b45 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewSubTaskAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/NewSubTaskAction.java
@@ -22,9 +22,11 @@ import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.operation.IRunnableWithProgress;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.StructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.LocalRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractAttributeFactory;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractTaskDataHandler;
@@ -34,9 +36,8 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPreferenceConstants;
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.NewTaskEditorInput;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
@@ -160,7 +161,7 @@ public class NewSubTaskAction extends Action implements IViewActionDelegate, IEx
 						TasksUiPreferenceConstants.LOCAL_SUB_TASKS_ENABLED)) {
 					selectedTask = (AbstractTask) selectedObject;
 				}
-			} else if (selectedObject instanceof AbstractTask) {
+			} else if (selectedObject instanceof ITask) {
 				selectedTask = (AbstractTask) selectedObject;
 
 				AbstractLegacyRepositoryConnector connector = (AbstractLegacyRepositoryConnector) TasksUi.getRepositoryManager()
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskAction.java
index d0fb115af..d97875e69 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskAction.java
@@ -10,8 +10,9 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.window.Window;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.IWorkbenchWindowActionDelegate;
@@ -40,7 +41,7 @@ public class OpenTaskAction extends ActionDelegate implements IWorkbenchWindowAc
 		}
 
 		Object result = dlg.getFirstResult();
-		if (result instanceof AbstractTask) {
+		if (result instanceof ITask) {
 			AbstractTask task = (AbstractTask) result;
 			if (dlg.getOpenInBrowser()) {
 				if (task.hasValidUrl()) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskListElementAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskListElementAction.java
index 6f98c4ced..b166664ee 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskListElementAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenTaskListElementAction.java
@@ -14,9 +14,10 @@ import org.eclipse.jface.action.Action;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.TreeViewer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.Event;
@@ -47,10 +48,10 @@ public class OpenTaskListElementAction extends Action {
 		ISelection selection = viewer.getSelection();
 		List<?> list = ((IStructuredSelection) selection).toList();
 		for (Object element : list) {
-			if (element instanceof AbstractTask && event != null && (event.keyCode & SWT.MOD1) != 0) {
+			if (element instanceof ITask && event != null && (event.keyCode & SWT.MOD1) != 0) {
 				TasksUiUtil.openTaskInBackground((AbstractTask) element, true);
-			} else if (element instanceof AbstractTask) {
-				TasksUiInternal.refreshAndOpenTaskListElement((AbstractTaskContainer) element);
+			} else if (element instanceof ITask) {
+				TasksUiInternal.refreshAndOpenTaskListElement((ITaskElement) element);
 			} else {
 				if (viewer.getExpandedState(element)) {
 					viewer.collapseToLevel(element, 1);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenWithBrowserAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenWithBrowserAction.java
index 32f409153..5c2fe58fd 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenWithBrowserAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/OpenWithBrowserAction.java
@@ -10,8 +10,9 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import java.util.Iterator;
 
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.ui.actions.BaseSelectionListenerAction;
 
@@ -43,13 +44,13 @@ public class OpenWithBrowserAction extends BaseSelectionListenerAction {
 
 	private void runWithSelection(Object selectedObject) {
 		String urlString = null;
-		if (selectedObject instanceof AbstractTask) {
+		if (selectedObject instanceof ITask) {
 			AbstractTask task = (AbstractTask) selectedObject;
 			if (task.hasValidUrl()) {
 				urlString = task.getUrl();
 			}
-		} else if (selectedObject instanceof AbstractTaskContainer) {
-			AbstractTaskContainer query = (AbstractTaskContainer) selectedObject;
+		} else if (selectedObject instanceof ITaskElement) {
+			ITaskElement query = (ITaskElement) selectedObject;
 			urlString = query.getUrl();
 		}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryCloneAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryCloneAction.java
index 74a06b238..330263b66 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryCloneAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryCloneAction.java
@@ -19,9 +19,9 @@ import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.ui.ITasksUiConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.ui.IViewActionDelegate;
 import org.eclipse.ui.IViewPart;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryExportAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryExportAction.java
index d0a163587..7db737d73 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryExportAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryExportAction.java
@@ -20,9 +20,9 @@ import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.StructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.FileDialog;
 import org.eclipse.swt.widgets.Shell;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryImportAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryImportAction.java
index f16b6324c..e5b46908b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryImportAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/QueryImportAction.java
@@ -17,9 +17,9 @@ import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.swt.widgets.FileDialog;
 import org.eclipse.swt.widgets.Shell;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RefreshRepositoryTasksAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RefreshRepositoryTasksAction.java
index aed33c15e..13eb87a4b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RefreshRepositoryTasksAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RefreshRepositoryTasksAction.java
@@ -17,7 +17,7 @@ import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IViewActionDelegate;
@@ -52,7 +52,7 @@ public class RefreshRepositoryTasksAction extends AbstractTaskRepositoryAction i
 		AbstractRepositoryConnector connector = TasksUi.getRepositoryManager().getRepositoryConnector(
 				repository.getConnectorKind());
 		if (connector != null) {
-			Set<AbstractTask> repositoryTasks = TasksUiPlugin.getTaskListManager().getTaskList().getTasks(
+			Set<ITask> repositoryTasks = TasksUiPlugin.getTaskListManager().getTaskList().getTasks(
 					repository.getRepositoryUrl());
 			TasksUiInternal.synchronizeTasks(connector, repositoryTasks, true, null);
 		}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RemoveFromCategoryAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RemoveFromCategoryAction.java
index 048517238..609338e24 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RemoveFromCategoryAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RemoveFromCategoryAction.java
@@ -12,10 +12,11 @@ import org.eclipse.jface.action.Action;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
 /**
@@ -41,7 +42,7 @@ public class RemoveFromCategoryAction extends Action {
 	public void run() {
 		ISelection selection = view.getViewer().getSelection();
 		for (Object selectedObject : ((IStructuredSelection) selection).toList()) {
-			if (selectedObject instanceof AbstractTask) {
+			if (selectedObject instanceof ITask) {
 				AbstractTask task = (AbstractTask) selectedObject;
 				AbstractTaskCategory category = TaskCategory.getParentTaskCategory(task);
 				if (category != null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RenameAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RenameAction.java
index c1989f0bb..b6dd9ee74 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RenameAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/RenameAction.java
@@ -8,11 +8,11 @@
 package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.SWT;
 import org.eclipse.ui.actions.BaseSelectionListenerAction;
 
@@ -37,8 +37,8 @@ public class RenameAction extends BaseSelectionListenerAction {
 	@Override
 	public void run() {
 		Object selectedObject = ((IStructuredSelection) this.view.getViewer().getSelection()).getFirstElement();
-		if (selectedObject instanceof AbstractTaskContainer) {
-			AbstractTaskContainer element = (AbstractTaskContainer) selectedObject;
+		if (selectedObject instanceof ITaskElement) {
+			ITaskElement element = (ITaskElement) selectedObject;
 			view.setInRenameAction(true);
 			view.getViewer().editElement(element, 0);
 			view.setInRenameAction(false);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ShowInTaskListAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ShowInTaskListAction.java
index 861ce2eed..58e812892 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ShowInTaskListAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ShowInTaskListAction.java
@@ -9,8 +9,9 @@
 package org.eclipse.mylyn.internal.tasks.ui.actions;
 
 import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.ui.actions.BaseSelectionListenerAction;
 
 /**
@@ -27,7 +28,7 @@ public class ShowInTaskListAction extends BaseSelectionListenerAction {
 		IStructuredSelection struSel = getStructuredSelection();
 		if (!struSel.isEmpty()) {
 			Object element = struSel.getFirstElement();
-			if (element instanceof AbstractTask) {
+			if (element instanceof ITask) {
 				TaskListView.openInActivePerspective();
 				TaskListView.getFromActivePerspective().selectedAndFocusTask((AbstractTask) element);
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeEditorAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeEditorAction.java
index 21db6a388..e0a6be8d5 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeEditorAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeEditorAction.java
@@ -16,7 +16,7 @@ import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.AbstractRepositoryTaskEditor;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
 import org.eclipse.ui.PlatformUI;
@@ -53,7 +53,7 @@ public class SynchronizeEditorAction extends BaseSelectionListenerAction {
 
 	@SuppressWarnings( { "deprecation" })
 	private void runWithSelection(final Object selectedObject) {
-		AbstractTask task = null;
+		ITask task = null;
 		if (selectedObject instanceof TaskEditor) {
 			TaskEditor editor = (TaskEditor) selectedObject;
 			task = editor.getTaskEditorInput().getTask();
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeSelectedAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeSelectedAction.java
index 491952d1e..de70df4bc 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeSelectedAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/SynchronizeSelectedAction.java
@@ -19,13 +19,14 @@ import java.util.Set;
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.core.data.ITaskDataManager;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
@@ -43,7 +44,7 @@ public class SynchronizeSelectedAction extends ActionDelegate implements IViewAc
 
 	private final Map<AbstractRepositoryConnector, List<AbstractRepositoryQuery>> queriesToSyncMap = new LinkedHashMap<AbstractRepositoryConnector, List<AbstractRepositoryQuery>>();
 
-	private final Map<AbstractRepositoryConnector, List<AbstractTask>> tasksToSyncMap = new LinkedHashMap<AbstractRepositoryConnector, List<AbstractTask>>();
+	private final Map<AbstractRepositoryConnector, List<ITask>> tasksToSyncMap = new LinkedHashMap<AbstractRepositoryConnector, List<ITask>>();
 
 	@Override
 	public void run(IAction action) {
@@ -66,12 +67,12 @@ public class SynchronizeSelectedAction extends ActionDelegate implements IViewAc
 					}
 				} else if (obj instanceof TaskCategory) {
 					TaskCategory cat = (TaskCategory) obj;
-					for (AbstractTask task : cat.getChildren()) {
+					for (ITask task : cat.getChildren()) {
 						AbstractRepositoryConnector client = TasksUi.getRepositoryManager().getRepositoryConnector(
 								task.getConnectorKind());
 						addTaskToSync(client, task);
 					}
-				} else if (obj instanceof AbstractTask) {
+				} else if (obj instanceof ITask) {
 					AbstractTask repositoryTask = (AbstractTask) obj;
 					AbstractRepositoryConnector client = TasksUi.getRepositoryManager().getRepositoryConnector(
 							repositoryTask.getConnectorKind());
@@ -112,9 +113,9 @@ public class SynchronizeSelectedAction extends ActionDelegate implements IViewAc
 			}
 			if (!tasksToSyncMap.isEmpty()) {
 				for (AbstractRepositoryConnector connector : tasksToSyncMap.keySet()) {
-					List<AbstractTask> tasksToSync = tasksToSyncMap.get(connector);
+					List<ITask> tasksToSync = tasksToSyncMap.get(connector);
 					if (tasksToSync != null && tasksToSync.size() > 0) {
-						TasksUiInternal.synchronizeTasks(connector, new HashSet<AbstractTask>(tasksToSync), true, null);
+						TasksUiInternal.synchronizeTasks(connector, new HashSet<ITask>(tasksToSync), true, null);
 					}
 				}
 			}
@@ -131,11 +132,11 @@ public class SynchronizeSelectedAction extends ActionDelegate implements IViewAc
 //		}		
 	}
 
-	private void addTaskToSync(AbstractRepositoryConnector client, AbstractTask repositoryTask) {
+	private void addTaskToSync(AbstractRepositoryConnector client, ITask repositoryTask) {
 		if (client != null) {
-			List<AbstractTask> tasksToSync = tasksToSyncMap.get(client);
+			List<ITask> tasksToSync = tasksToSyncMap.get(client);
 			if (tasksToSync == null) {
-				tasksToSync = new ArrayList<AbstractTask>();
+				tasksToSync = new ArrayList<ITask>();
 				tasksToSyncMap.put(client, tasksToSync);
 			}
 			tasksToSync.add(repositoryTask);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskActivateAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskActivateAction.java
index f5d6b9382..88991624e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskActivateAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskActivateAction.java
@@ -13,7 +13,7 @@ import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IViewActionDelegate;
 import org.eclipse.ui.IViewPart;
@@ -40,7 +40,7 @@ public class TaskActivateAction extends Action implements IViewActionDelegate {
 		run(TaskListView.getFromActivePerspective().getSelectedTask());
 	}
 
-	public void run(AbstractTask task) {
+	public void run(ITask task) {
 		if (task != null && !task.isActive()) {
 			TasksUi.getTaskActivityManager().activateTask(task);
 		}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskDeactivateAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskDeactivateAction.java
index 1bdebe8a5..a8d0e1b34 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskDeactivateAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskDeactivateAction.java
@@ -15,7 +15,7 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
 /**
@@ -31,7 +31,7 @@ public class TaskDeactivateAction extends Action {
 		setImageDescriptor(TasksUiImages.CONTEXT_INACTIVE_EMPTY);
 	}
 
-	public void run(AbstractTask task) {
+	public void run(ITask task) {
 		try {
 			if (task != null) {
 				TasksUi.getTaskActivityManager().deactivateTask(task);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskExportAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskExportAction.java
index 90d4cb44e..bfe549570 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskExportAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskExportAction.java
@@ -20,9 +20,10 @@ import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.StructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.DirectoryDialog;
 import org.eclipse.swt.widgets.FileDialog;
@@ -64,7 +65,7 @@ public class TaskExportAction extends Action implements IViewActionDelegate {
 		if (selection instanceof StructuredSelection) {
 			List<?> selectedObjects = ((StructuredSelection) selection).toList();
 			for (Object selectedObject : selectedObjects) {
-				if (selectedObject instanceof AbstractTask) {
+				if (selectedObject instanceof ITask) {
 					selectedQueries.add((AbstractTask) selectedObject);
 				}
 			}
@@ -123,7 +124,7 @@ public class TaskExportAction extends Action implements IViewActionDelegate {
 		return;
 	}
 
-	private String encodeName(AbstractTask task) {
+	private String encodeName(ITask task) {
 		String fileName = task.getSummary();
 		if (fileName.length() > 50) {
 			fileName = fileName.substring(0, 50);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskImportAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskImportAction.java
index 5d1f49b62..a953df590 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskImportAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskImportAction.java
@@ -20,12 +20,12 @@ import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.mylyn.internal.context.core.ContextCorePlugin;
 import org.eclipse.mylyn.internal.context.core.InteractionContext;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.internal.tasks.ui.ITasksUiConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.widgets.FileDialog;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskSelectionDialog.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskSelectionDialog.java
index 60907a881..b70213143 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskSelectionDialog.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/TaskSelectionDialog.java
@@ -40,6 +40,8 @@ import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.window.Window;
 import org.eclipse.jface.wizard.WizardDialog;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonColors;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivationHistory;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.internal.tasks.ui.TaskSearchPage;
@@ -50,8 +52,8 @@ import org.eclipse.mylyn.internal.tasks.ui.views.TaskListFilteredTree;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
 import org.eclipse.mylyn.internal.tasks.ui.workingsets.TaskWorkingSetUpdater;
 import org.eclipse.mylyn.internal.tasks.ui.workingsets.WorkingSetLabelComparator;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.search.internal.ui.SearchDialog;
 import org.eclipse.swt.SWT;
@@ -230,7 +232,7 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 
 		@Override
 		public synchronized boolean remove(Object object) {
-			taskActivationHistory.removeTask((AbstractTask) object);
+			taskActivationHistory.removeTask((ITask) object);
 			return history.remove(object);
 		}
 
@@ -256,7 +258,7 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 	 */
 	private class TasksFilter extends ItemsFilter {
 
-		private Set<AbstractTask> allTasksFromWorkingSets;
+		private Set<ITask> allTasksFromWorkingSets;
 
 		/**
 		 * Stores the task containers from selected working set; empty, which can come from no working set selection or
@@ -300,7 +302,7 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 
 		@Override
 		public boolean isConsistentItem(Object item) {
-			return item instanceof AbstractTask;
+			return item instanceof ITask;
 		}
 
 		@Override
@@ -326,10 +328,10 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 
 		@Override
 		public boolean matchItem(Object item) {
-			if (!(item instanceof AbstractTask)) {
+			if (!(item instanceof ITask)) {
 				return false;
 			}
-			if (!showCompletedTasks && ((AbstractTask) item).isCompleted()) {
+			if (!showCompletedTasks && ((ITask) item).isCompleted()) {
 				return false;
 			}
 			if (!elements.isEmpty()) {
@@ -344,8 +346,8 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 		}
 
 		private void populateTasksFromWorkingSets() {
-			allTasksFromWorkingSets = new HashSet<AbstractTask>(1000);
-			for (AbstractTaskContainer container : elements) {
+			allTasksFromWorkingSets = new HashSet<ITask>(1000);
+			for (ITaskElement container : elements) {
 				allTasksFromWorkingSets.addAll(container.getChildren());
 			}
 		}
@@ -556,7 +558,7 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 
 		SubProgressMonitor subMonitor = new SubProgressMonitor(progressMonitor, 90);
 		subMonitor.beginTask("Scanning tasks", allTasks.size());
-		for (AbstractTask task : allTasks) {
+		for (ITask task : allTasks) {
 			contentProvider.add(task, itemsFilter);
 			subMonitor.worked(1);
 		}
@@ -712,7 +714,7 @@ public class TaskSelectionDialog extends FilteredItemsSelectionDialog {
 
 	@Override
 	protected IStatus validateItem(Object item) {
-		if (item instanceof AbstractTask) {
+		if (item instanceof ITask) {
 			return Status.OK_STATUS;
 		}
 		return new Status(IStatus.ERROR, TasksUiPlugin.ID_PLUGIN, "Selected item is not a task");
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ToggleTaskActivationAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ToggleTaskActivationAction.java
index 25372937e..71d45c07b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ToggleTaskActivationAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/actions/ToggleTaskActivationAction.java
@@ -11,7 +11,7 @@ package org.eclipse.mylyn.internal.tasks.ui.actions;
 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.IToolBarManager;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskActivityListener;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
@@ -26,7 +26,7 @@ public class ToggleTaskActivationAction extends Action implements ITaskActivityL
 
 	private static final String LABEL_DEACTIVATE = "Deactivate Task";
 
-	private final AbstractTask task;
+	private final ITask task;
 
 	private final IToolBarManager toolBarManager;
 
@@ -36,7 +36,7 @@ public class ToggleTaskActivationAction extends Action implements ITaskActivityL
 	 * @param toolBarManager
 	 * 		cannot be null
 	 */
-	public ToggleTaskActivationAction(AbstractTask task, IToolBarManager toolBarManager) {
+	public ToggleTaskActivationAction(ITask task, IToolBarManager toolBarManager) {
 		this.task = task;
 		this.toolBarManager = toolBarManager;
 		setId(ID);
@@ -71,21 +71,21 @@ public class ToggleTaskActivationAction extends Action implements ITaskActivityL
 //		toolBarManager.add(this);
 	}
 
-	public void taskActivated(AbstractTask task) {
+	public void taskActivated(ITask task) {
 		update();
 		toolBarManager.update(true);
 	}
 
-	public void taskDeactivated(AbstractTask task) {
+	public void taskDeactivated(ITask task) {
 		update();
 		toolBarManager.update(true);
 	}
 
-	public void preTaskActivated(AbstractTask task) {
+	public void preTaskActivated(ITask task) {
 		// ignore
 	}
 
-	public void preTaskDeactivated(AbstractTask task) {
+	public void preTaskDeactivated(ITask task) {
 		// ignore		
 	}
 
@@ -93,7 +93,7 @@ public class ToggleTaskActivationAction extends Action implements ITaskActivityL
 		// ignore
 	}
 
-	public void elapsedTimeUpdated(AbstractTask task, long newElapsedTime) {
+	public void elapsedTimeUpdated(ITask task, long newElapsedTime) {
 		// ignore
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/AbstractTaskListViewHandler.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/AbstractTaskListViewHandler.java
index ee8ce3af2..fae59c85a 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/AbstractTaskListViewHandler.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/AbstractTaskListViewHandler.java
@@ -15,7 +15,7 @@ import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.jface.viewers.ITreeSelection;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.ui.IViewSite;
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.IWorkbenchSite;
@@ -43,13 +43,13 @@ public abstract class AbstractTaskListViewHandler extends AbstractHandler {
 		ITreeSelection selection = (ITreeSelection) taskListView.getViewer().getSelection();
 		for (Iterator<?> it = selection.iterator(); it.hasNext();) {
 			Object item = it.next();
-			if (item instanceof AbstractTaskContainer) {
-				execute(event, taskListView, (AbstractTaskContainer) item);
+			if (item instanceof ITaskElement) {
+				execute(event, taskListView, (ITaskElement) item);
 			}
 		}
 	}
 
-	protected void execute(ExecutionEvent event, TaskListView taskListView, AbstractTaskContainer item) {
+	protected void execute(ExecutionEvent event, TaskListView taskListView, ITaskElement item) {
 	}
 
 }
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenSelectedTaskHandler.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenSelectedTaskHandler.java
index 3ec17fd1c..f5e9b4be1 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenSelectedTaskHandler.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenSelectedTaskHandler.java
@@ -9,9 +9,10 @@
 package org.eclipse.mylyn.internal.tasks.ui.commands;
 
 import org.eclipse.core.commands.ExecutionEvent;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 
 /**
@@ -20,8 +21,8 @@ import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 public class OpenSelectedTaskHandler extends AbstractTaskListViewHandler {
 
 	@Override
-	protected void execute(ExecutionEvent event, TaskListView taskListView, AbstractTaskContainer item) {
-		if (item instanceof AbstractTask) {
+	protected void execute(ExecutionEvent event, TaskListView taskListView, ITaskElement item) {
+		if (item instanceof ITask) {
 			TasksUiUtil.openTaskInBackground((AbstractTask) item, true);
 		}
 	}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenTaskListElementPropertiesHandler.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenTaskListElementPropertiesHandler.java
index c55dcecf7..d095dda64 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenTaskListElementPropertiesHandler.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/OpenTaskListElementPropertiesHandler.java
@@ -9,11 +9,11 @@
 package org.eclipse.mylyn.internal.tasks.ui.commands;
 
 import org.eclipse.core.commands.ExecutionEvent;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * @author Steffen Pingel
@@ -21,7 +21,7 @@ import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
 public class OpenTaskListElementPropertiesHandler extends AbstractTaskListViewHandler {
 
 	@Override
-	protected void execute(ExecutionEvent event, TaskListView taskListView, AbstractTaskContainer item) {
+	protected void execute(ExecutionEvent event, TaskListView taskListView, ITaskElement item) {
 		if (item instanceof TaskCategory || item instanceof AbstractRepositoryQuery) {
 			TasksUiInternal.refreshAndOpenTaskListElement(item);
 		}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/RemoteTaskSelectionDialog.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/RemoteTaskSelectionDialog.java
index 11e701e9a..f186c65b5 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/RemoteTaskSelectionDialog.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/commands/RemoteTaskSelectionDialog.java
@@ -33,6 +33,9 @@ import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerFilter;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.ITaskRepositoryFilter;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.internal.tasks.core.TaskRepositoryManager;
@@ -41,9 +44,8 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskElementLabelProvider;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskRepositoryLabelProvider;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
@@ -127,10 +129,10 @@ public class RemoteTaskSelectionDialog extends SelectionStatusDialog {
 				}
 
 				// Only shows exact task matches
-				if (!(element instanceof AbstractTask)) {
+				if (!(element instanceof ITask)) {
 					return false;
 				}
-				AbstractTask task = (AbstractTask) element;
+				ITask task = (ITask) element;
 				String taskId = task.getTaskKey();
 				for (String id : selectedIds) {
 					if (id.equals(taskId)) {
@@ -227,8 +229,8 @@ public class RemoteTaskSelectionDialog extends SelectionStatusDialog {
 
 			@Override
 			public String getText(Object element) {
-				if (element instanceof AbstractTaskContainer) {
-					return ((AbstractTaskContainer) element).getSummary();
+				if (element instanceof ITaskElement) {
+					return ((ITaskElement) element).getSummary();
 				}
 				return super.getText(element);
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractNewRepositoryTaskEditor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractNewRepositoryTaskEditor.java
index fb4e4b7fa..41b7b5188 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractNewRepositoryTaskEditor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractNewRepositoryTaskEditor.java
@@ -23,6 +23,9 @@ import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.ScheduleDatePicker;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
@@ -30,9 +33,7 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.editors.RepositoryTaskOutlineNode;
 import org.eclipse.mylyn.internal.tasks.ui.editors.RepositoryTaskSelection;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditorInput;
@@ -378,7 +379,7 @@ public abstract class AbstractNewRepositoryTaskEditor extends AbstractRepository
 
 		});
 
-		for (AbstractTaskContainer category : categories) {
+		for (ITaskElement category : categories) {
 			categoryChooser.add(category.getSummary());
 		}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractRepositoryTaskEditor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractRepositoryTaskEditor.java
index 89ac05f6e..6c9755532 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractRepositoryTaskEditor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/AbstractRepositoryTaskEditor.java
@@ -74,7 +74,11 @@ import org.eclipse.mylyn.commons.core.DateUtil;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonThemes;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.CommentQuoter;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractDuplicateDetector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractTaskDataHandler;
@@ -114,15 +118,12 @@ import org.eclipse.mylyn.internal.tasks.ui.search.SearchHitCollector;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.UpdateRepositoryConfigurationAction;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskListChangeListener;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskContainerDelta;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
@@ -418,11 +419,11 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 
 		@Override
 		public void containersChanged(Set<TaskContainerDelta> containers) {
-			AbstractTask taskToRefresh = null;
+			ITask taskToRefresh = null;
 			for (TaskContainerDelta taskContainerDelta : containers) {
 				if (repositoryTask != null && repositoryTask.equals(taskContainerDelta.getContainer())) {
 					if (taskContainerDelta.getKind().equals(TaskContainerDelta.Kind.CONTENT)) {
-						taskToRefresh = (AbstractTask) taskContainerDelta.getContainer();
+						taskToRefresh = (ITask) taskContainerDelta.getContainer();
 						break;
 					}
 				}
@@ -706,8 +707,7 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 
 		if (taskData != null && !taskData.isNew()) {
 			if (repositoryTask != null) {
-				clearOutgoingAction = new ClearOutgoingAction(
-						Collections.singletonList((AbstractTaskContainer) repositoryTask));
+				clearOutgoingAction = new ClearOutgoingAction(Collections.singletonList((ITaskElement) repositoryTask));
 
 				if (clearOutgoingAction.isEnabled()) {
 					toolBarManager.add(clearOutgoingAction);
@@ -1258,8 +1258,8 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 		if (duplicateDetector != null) {
 			AbstractRepositoryQuery duplicatesQuery = duplicateDetector.getDuplicatesQuery(repository, taskData);
 			if (duplicatesQuery != null) {
-				SearchHitCollector collector = new SearchHitCollector(TasksUi.getTaskList(),
-						repository, duplicatesQuery);
+				SearchHitCollector collector = new SearchHitCollector(TasksUi.getTaskList(), repository,
+						duplicatesQuery);
 				NewSearchUI.runQueryInBackground(collector);
 				return true;
 			}
@@ -1698,8 +1698,7 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 				SWT.PUSH);
 		attachScreenshotButton.setImage(CommonImages.getImage(CommonImages.IMAGE_CAPTURE));
 
-		final AbstractTask task = TasksUi.getTaskList().getTask(repository.getRepositoryUrl(),
-				taskData.getTaskId());
+		final ITask task = TasksUi.getTaskList().getTask(repository.getRepositoryUrl(), taskData.getTaskId());
 		if (task == null) {
 			attachFileButton.setEnabled(false);
 			attachScreenshotButton.setEnabled(false);
@@ -1741,8 +1740,7 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 				}
 
 				public void widgetSelected(SelectionEvent e) {
-					AbstractTask task = TasksUi.getTaskList().getTask(
-							repository.getRepositoryUrl(), taskData.getTaskId());
+					ITask task = TasksUi.getTaskList().getTask(repository.getRepositoryUrl(), taskData.getTaskId());
 					if (task == null) {
 						// Should not happen
 						return;
@@ -2800,8 +2798,7 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 
 		toolkit.createLabel(buttonComposite, "    ");
 
-		AbstractTask task = TasksUi.getTaskList().getTask(repository.getRepositoryUrl(),
-				taskData.getTaskId());
+		ITask task = TasksUi.getTaskList().getTask(repository.getRepositoryUrl(), taskData.getTaskId());
 		if (attachContextEnabled && task != null) {
 			addAttachContextButton(buttonComposite, task);
 		}
@@ -3447,7 +3444,7 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 		return false;
 	}
 
-	protected void addAttachContextButton(Composite buttonComposite, AbstractTask task) {
+	protected void addAttachContextButton(Composite buttonComposite, ITask task) {
 		attachContextButton = toolkit.createButton(buttonComposite, "Attach Context", SWT.CHECK);
 		attachContextButton.setImage(CommonImages.getImage(TasksUiImages.CONTEXT_ATTACH));
 	}
@@ -3605,8 +3602,8 @@ public abstract class AbstractRepositoryTaskEditor extends TaskFormPage {
 											"Task could not be created. No additional information was provided by the connector."));
 						}
 					} else {
-						modifiedTask = TasksUi.getTaskList().getTask(
-								repository.getRepositoryUrl(), taskData.getTaskId());
+						modifiedTask = TasksUi.getTaskList().getTask(repository.getRepositoryUrl(),
+								taskData.getTaskId());
 					}
 
 					// Synchronization accounting...
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/RepositoryTaskEditorInput.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/RepositoryTaskEditorInput.java
index 24fce83ac..fa37e7ad9 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/RepositoryTaskEditorInput.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/RepositoryTaskEditorInput.java
@@ -7,7 +7,7 @@
  *******************************************************************************/
 package org.eclipse.mylyn.internal.tasks.ui.deprecated;
 
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditorInput;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/TaskFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/TaskFactory.java
index 8daf95b75..832f936aa 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/TaskFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/deprecated/TaskFactory.java
@@ -14,17 +14,18 @@ import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.core.runtime.SubProgressMonitor;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskDataStorageManager;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.core.data.TaskDataManager;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractTaskDataHandler;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.ITaskFactory;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
 /**
@@ -93,7 +94,7 @@ public class TaskFactory implements ITaskFactory {
 				synchManager.saveIncoming(repositoryTask, taskData, forced);
 				connector.updateTaskFromTaskData(repository, repositoryTask, taskData);
 				if (dataHandler != null) {
-					for (AbstractTask child : repositoryTask.getChildren()) {
+					for (ITask child : repositoryTask.getChildren()) {
 						taskList.removeFromContainer(repositoryTask, child);
 					}
 					Set<String> subTaskIds = dataHandler.getSubTaskIds(taskData);
@@ -134,7 +135,9 @@ public class TaskFactory implements ITaskFactory {
 				taskDataManager.setNewTaskData(taskData);
 
 				if (retrieveSubTasks) {
-					monitor.beginTask("Creating task", connector.getLegacyTaskDataHandler().getSubTaskIds(taskData).size());
+					monitor.beginTask("Creating task", connector.getLegacyTaskDataHandler()
+							.getSubTaskIds(taskData)
+							.size());
 					for (String subId : connector.getLegacyTaskDataHandler().getSubTaskIds(taskData)) {
 						if (subId == null || subId.trim().equals("")) {
 							continue;
@@ -162,7 +165,8 @@ public class TaskFactory implements ITaskFactory {
 		AbstractTask repositoryTask = taskList.getTask(repository.getRepositoryUrl(), id);
 		if (repositoryTask == null && connector.getLegacyTaskDataHandler() != null) {
 			RepositoryTaskData taskData = null;
-			taskData = connector.getLegacyTaskDataHandler().getTaskData(repository, id, new SubProgressMonitor(monitor, 1));
+			taskData = connector.getLegacyTaskDataHandler().getTaskData(repository, id,
+					new SubProgressMonitor(monitor, 1));
 			if (taskData != null) {
 				repositoryTask = createTaskFromTaskData(connector, repository, taskData, retrieveSubTasks,
 						new SubProgressMonitor(monitor, 1));
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/CategoryEditorInput.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/CategoryEditorInput.java
index 62a8a065a..63ee5a67f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/CategoryEditorInput.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/CategoryEditorInput.java
@@ -12,9 +12,9 @@ import java.util.HashSet;
 import java.util.Set;
 
 import org.eclipse.jface.resource.ImageDescriptor;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
 import org.eclipse.ui.IEditorInput;
 import org.eclipse.ui.IPersistableElement;
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryCompletionProcessor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryCompletionProcessor.java
index e7c77acd9..c96f768eb 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryCompletionProcessor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryCompletionProcessor.java
@@ -26,6 +26,7 @@ import org.eclipse.jface.text.contentassist.IContentAssistProcessor;
 import org.eclipse.jface.text.contentassist.IContextInformation;
 import org.eclipse.jface.text.contentassist.IContextInformationValidator;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivationHistory;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
@@ -35,7 +36,7 @@ import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskElementLabelProvider;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditorInput;
@@ -56,7 +57,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 
 		public static final String LABEL_SEPARATOR = " -------------------------------------------- ";
 
-		private final Set<AbstractTask> addedTasks = new HashSet<AbstractTask>();
+		private final Set<ITask> addedTasks = new HashSet<ITask>();
 
 		private boolean addSeparator;
 
@@ -71,7 +72,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 			this.prefix = extractPrefix(viewer, offset).toLowerCase();
 		}
 
-		private void addProposal(AbstractTask task, String replacement, boolean includeTaskPrefix) {
+		private void addProposal(ITask task, String replacement, boolean includeTaskPrefix) {
 			if (addSeparator) {
 				if (!addedTasks.isEmpty()) {
 					resultList.add(createSeparator());
@@ -97,7 +98,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 			}
 		}
 
-		public void addTask(AbstractTask task) {
+		public void addTask(ITask task) {
 			if (addedTasks.contains(task)) {
 				return;
 			}
@@ -112,7 +113,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 			}
 		}
 
-		private String getReplacement(AbstractTask task, String text, boolean includeTaskPrefix) {
+		private String getReplacement(ITask task, String text, boolean includeTaskPrefix) {
 			// add an absolute reference to the task if the viewer does not have a repository
 			if (taskRepository == null || text == null
 					|| !taskRepository.getRepositoryUrl().equals(task.getRepositoryUrl())) {
@@ -126,7 +127,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 			}
 		}
 
-		private boolean containsPrefix(AbstractTask task) {
+		private boolean containsPrefix(ITask task) {
 			String searchTest = getTaskPrefix(task) + " " + labelProvider.getText(task);
 			String[] tokens = searchTest.split("\\s");
 			for (String token : tokens) {
@@ -170,14 +171,14 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 
 		public void filterTasks(List<AbstractTask> tasks) {
 			for (Iterator<AbstractTask> it = tasks.iterator(); it.hasNext();) {
-				AbstractTask task = it.next();
+				ITask task = it.next();
 				if (!select(task)) {
 					it.remove();
 				}
 			}
 		}
 
-		private boolean select(AbstractTask task) {
+		private boolean select(ITask task) {
 			return !(task instanceof LocalTask) //
 					&& (taskRepository == null || task.getRepositoryUrl().equals(taskRepository.getRepositoryUrl()));
 		}
@@ -235,7 +236,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 					try {
 						if (editorReferences[i].getEditorInput() instanceof TaskEditorInput) {
 							TaskEditorInput input = (TaskEditorInput) editorReferences[i].getEditorInput();
-							AbstractTask task = input.getTask();
+							ITask task = input.getTask();
 							if (task != null && !(task instanceof LocalTask)) {
 								proposalComputer.addTask(task);
 								count++;
@@ -297,7 +298,7 @@ public class RepositoryCompletionProcessor implements IContentAssistProcessor {
 		return null;
 	}
 
-	private String getTaskPrefix(AbstractTask task) {
+	private String getTaskPrefix(ITask task) {
 		AbstractRepositoryConnector connector = TasksUiPlugin.getConnector(task.getConnectorKind());
 		String prefix = connector.getTaskIdPrefix();
 		// FIXME work around for Trac "#" prefix
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTaskEditorDropListener.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTaskEditorDropListener.java
index d14958b93..d0eb36f6e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTaskEditorDropListener.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTaskEditorDropListener.java
@@ -12,11 +12,11 @@ import java.io.File;
 
 import org.eclipse.jface.dialogs.IMessageProvider;
 import org.eclipse.jface.window.Window;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.AbstractRepositoryTaskEditor;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizard;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizardDialog;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.dnd.DND;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTextViewerConfiguration.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTextViewerConfiguration.java
index 9b28f6e18..f1518fb03 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTextViewerConfiguration.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/RepositoryTextViewerConfiguration.java
@@ -36,7 +36,7 @@ import org.eclipse.jface.text.rules.SingleLineRule;
 import org.eclipse.jface.text.rules.Token;
 import org.eclipse.jface.text.source.ISourceViewer;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonColors;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TaskHyperlink;
@@ -142,7 +142,7 @@ public class RepositoryTextViewerConfiguration extends TextSourceViewerConfigura
 		 * Stores which task a tooltip is being displayed for. It is used to avoid having the same tooltip being set
 		 * multiple times while you move the mouse over a task hyperlink (bug#209409)
 		 */
-		private AbstractTask currentTaskHyperlink;
+		private ITask currentTaskHyperlink;
 
 		private TaskTextViewerHyperlinkPresenter(Color color, ISourceViewer sourceViewer) {
 			super(color);
@@ -174,7 +174,7 @@ public class RepositoryTextViewerConfiguration extends TextSourceViewerConfigura
 				ITaskList taskList = TasksUi.getTaskList();
 				String repositoryUrl = hyperlink.getRepository().getRepositoryUrl();
 
-				AbstractTask task = taskList.getTask(repositoryUrl, hyperlink.getTaskId());
+				ITask task = taskList.getTask(repositoryUrl, hyperlink.getTaskId());
 				if (task == null) {
 					task = taskList.getTaskByKey(repositoryUrl, hyperlink.getTaskId());
 				}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskAttachmentEditorInput.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskAttachmentEditorInput.java
index a6233cd0e..e460cde48 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskAttachmentEditorInput.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskAttachmentEditorInput.java
@@ -20,7 +20,7 @@ import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskAttachment;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskAttachmentHandler;
@@ -113,13 +113,13 @@ public class TaskAttachmentEditorInput extends PlatformObject implements IStorag
 
 		private final TaskRepository taskRepository;
 
-		private final AbstractTask task;
+		private final ITask task;
 
 		private final TaskAttribute attachmentAttribute;
 
 		private final String name;
 
-		public TaskAttachmentStorage(TaskRepository taskRepository, AbstractTask task,
+		public TaskAttachmentStorage(TaskRepository taskRepository, ITask task,
 				TaskAttribute attachmentAttribute, String name) {
 			this.taskRepository = taskRepository;
 			this.task = task;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionContributor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionContributor.java
index 6abf7f43c..8839fde49 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionContributor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionContributor.java
@@ -28,6 +28,7 @@ import org.eclipse.jface.viewers.ISelectionProvider;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.AddExistingTaskJob;
 import org.eclipse.mylyn.internal.tasks.ui.IDynamicSubMenuContributor;
@@ -47,9 +48,8 @@ import org.eclipse.mylyn.internal.tasks.ui.deprecated.AbstractRepositoryTaskEdit
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.NewTaskEditorInput;
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.RepositoryTaskEditorInput;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.AbstractTaskEditorPage;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
@@ -216,7 +216,7 @@ public class TaskEditorActionContributor extends MultiPageEditorActionBarContrib
 			return;
 		}
 
-		final AbstractTask task = editor.getTaskEditorInput().getTask();
+		final ITask task = editor.getTaskEditorInput().getTask();
 		if (task == null) {
 			return;
 		} else {
@@ -260,12 +260,12 @@ public class TaskEditorActionContributor extends MultiPageEditorActionBarContrib
 				for (IDynamicSubMenuContributor contributor : TasksUiPlugin.getDefault().getDynamicMenuMap().get(
 						menuPath)) {
 					if (TaskListView.ID_SEPARATOR_TASKS.equals(menuPath)) {
-						List<AbstractTaskContainer> selectedElements = new ArrayList<AbstractTaskContainer>();
+						List<ITaskElement> selectedElements = new ArrayList<ITaskElement>();
 						selectedElements.add(task);
 						MenuManager subMenuManager = contributor.getSubMenuManager(selectedElements);
 						if (subMenuManager != null) {
 							subMenuManager.setVisible(selectedElements.size() > 0
-									&& selectedElements.get(0) instanceof AbstractTask);
+									&& selectedElements.get(0) instanceof ITask);
 							manager.add(subMenuManager);
 						}
 					}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionPart.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionPart.java
index 3015f55a4..209537d6c 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionPart.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorActionPart.java
@@ -15,10 +15,11 @@ import java.util.List;
 
 import org.eclipse.jface.layout.GridDataFactory;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
 import org.eclipse.mylyn.tasks.core.data.TaskAttributeProperties;
@@ -161,7 +162,7 @@ public class TaskEditorActionPart extends AbstractTaskEditorPart {
 			}
 
 		});
-		for (AbstractTaskContainer category : categories) {
+		for (ITaskElement category : categories) {
 			categoryChooser.add(category.getSummary());
 		}
 		categoryChooser.select(0);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorDescriptionPart.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorDescriptionPart.java
index b5605d863..96a11ad9b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorDescriptionPart.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorDescriptionPart.java
@@ -17,12 +17,12 @@ import java.util.Set;
 
 import org.eclipse.jface.action.ToolBarManager;
 import org.eclipse.jface.layout.GridDataFactory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.IdentityAttributeFactory;
 import org.eclipse.mylyn.internal.tasks.core.data.TaskDataUtil;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractDuplicateDetector;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.search.SearchHitCollector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.search.ui.NewSearchUI;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorInputFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorInputFactory.java
index 171ee1163..13c8d50a0 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorInputFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorInputFactory.java
@@ -12,8 +12,8 @@ import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditorInput;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorPlanningPart.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorPlanningPart.java
index 47cdbad7d..4c52fbc67 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorPlanningPart.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskEditorPlanningPart.java
@@ -16,7 +16,7 @@ import org.eclipse.mylyn.internal.provisional.commons.ui.DatePicker;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPreferenceConstants;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.editors.AbstractTaskEditorPart;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.layout.GridData;
@@ -48,7 +48,7 @@ public class TaskEditorPlanningPart extends AbstractTaskEditorPart {
 
 	@Override
 	public void commit(boolean onSave) {
-		AbstractTask task = getTaskEditorPage().getTask();
+		ITask task = getTaskEditorPage().getTask();
 		Assert.isNotNull(task);
 
 		Calendar selectedDate = null;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskPlanningEditor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskPlanningEditor.java
index 1231b6eea..305f73f34 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskPlanningEditor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/editors/TaskPlanningEditor.java
@@ -28,9 +28,11 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.provisional.commons.ui.DatePicker;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.LocalRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.ui.RetrieveTitleFromUrlJob;
 import org.eclipse.mylyn.internal.tasks.ui.ScheduleDatePicker;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
@@ -39,13 +41,12 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiPreferenceConstants;
 import org.eclipse.mylyn.internal.tasks.ui.actions.ToggleTaskActivationAction;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
 import org.eclipse.mylyn.monitor.ui.MonitorUi;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskActivityListener;
 import org.eclipse.mylyn.tasks.core.ITaskListChangeListener;
 import org.eclipse.mylyn.tasks.core.TaskActivityAdapter;
 import org.eclipse.mylyn.tasks.core.TaskContainerDelta;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
@@ -118,7 +119,7 @@ public class TaskPlanningEditor extends TaskFormPage {
 
 	private ScheduleDatePicker scheduleDatePicker;
 
-	private AbstractTask task;
+	private ITask task;
 
 	private Composite editorComposite;
 
@@ -153,7 +154,7 @@ public class TaskPlanningEditor extends TaskFormPage {
 		@Override
 		public void containersChanged(Set<TaskContainerDelta> containers) {
 			for (TaskContainerDelta taskContainerDelta : containers) {
-				if (taskContainerDelta.getContainer() instanceof AbstractTask) {
+				if (taskContainerDelta.getContainer() instanceof ITask) {
 					final AbstractTask updateTask = (AbstractTask) taskContainerDelta.getContainer();
 					if (updateTask != null && task != null
 							&& updateTask.getHandleIdentifier().equals(task.getHandleIdentifier())) {
@@ -399,7 +400,7 @@ public class TaskPlanningEditor extends TaskFormPage {
 
 		TaskRepository repository = null;
 		if (task != null && !(task instanceof LocalTask)) {
-			AbstractTask repositoryTask = task;
+			ITask repositoryTask = task;
 			repository = TasksUi.getRepositoryManager().getRepository(repositoryTask.getConnectorKind(),
 					repositoryTask.getRepositoryUrl());
 		}
@@ -788,7 +789,7 @@ public class TaskPlanningEditor extends TaskFormPage {
 		timingListener = new TaskActivityAdapter() {
 
 			@Override
-			public void elapsedTimeUpdated(AbstractTask task, long newElapsedTime) {
+			public void elapsedTimeUpdated(ITask task, long newElapsedTime) {
 				if (task.equals(TaskPlanningEditor.this.task)) {
 					String elapsedTimeString = NO_TIME_ELAPSED;
 					try {
@@ -868,7 +869,7 @@ public class TaskPlanningEditor extends TaskFormPage {
 
 		TaskRepository repository = null;
 		if (task != null && !(task instanceof LocalTask)) {
-			AbstractTask repositoryTask = task;
+			ITask repositoryTask = task;
 			repository = TasksUi.getRepositoryManager().getRepository(repositoryTask.getConnectorKind(),
 					repositoryTask.getRepositoryUrl());
 		}
@@ -900,7 +901,7 @@ public class TaskPlanningEditor extends TaskFormPage {
 		toolkit.paintBordersFor(container);
 	}
 
-	private String getTaskDateString(AbstractTask task) {
+	private String getTaskDateString(ITask task) {
 
 		if (task == null) {
 			return "";
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotification.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotification.java
index c01603d84..5eb28cc1e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotification.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotification.java
@@ -13,9 +13,10 @@ import java.util.Date;
 import org.eclipse.jface.viewers.DecoratingLabelProvider;
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotification;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskElementLabelProvider;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.ui.PlatformUI;
 
@@ -25,7 +26,7 @@ import org.eclipse.ui.PlatformUI;
  */
 public class TaskListNotification extends AbstractNotification {
 
-	protected final AbstractTask task;
+	protected final ITask task;
 
 	protected Date date;
 
@@ -34,7 +35,7 @@ public class TaskListNotification extends AbstractNotification {
 	private final DecoratingLabelProvider labelProvider = new DecoratingLabelProvider(
 			new TaskElementLabelProvider(true), PlatformUI.getWorkbench().getDecoratorManager().getLabelDecorator());
 
-	public TaskListNotification(AbstractTask task) {
+	public TaskListNotification(ITask task) {
 		this.task = task;
 	}
 
@@ -67,7 +68,7 @@ public class TaskListNotification extends AbstractNotification {
 		return labelProvider.getImage(task);
 	}
 
-	protected AbstractTask getTask() {
+	protected ITask getTask() {
 		return task;
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationPopup.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationPopup.java
index 2ab69fd69..6d9740d2f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationPopup.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationPopup.java
@@ -13,10 +13,10 @@ import java.util.List;
 import org.eclipse.jface.layout.GridDataFactory;
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotification;
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotificationPopup;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.TaskListHyperlink;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.MouseAdapter;
 import org.eclipse.swt.events.MouseEvent;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationQueryIncoming.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationQueryIncoming.java
index d7a45de8a..49757c078 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationQueryIncoming.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationQueryIncoming.java
@@ -11,14 +11,14 @@ package org.eclipse.mylyn.internal.tasks.ui.notifications;
 import java.util.Date;
 
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotification;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * @author Rob Elves
  */
 public class TaskListNotificationQueryIncoming extends TaskListNotification {
 
-	public TaskListNotificationQueryIncoming(AbstractTask task) {
+	public TaskListNotificationQueryIncoming(ITask task) {
 		super(task);
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationReminder.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationReminder.java
index d9a12a9f5..a2f351fd5 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationReminder.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/notifications/TaskListNotificationReminder.java
@@ -12,7 +12,7 @@ import java.util.Date;
 
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotification;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.swt.graphics.Image;
 
 /**
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/CreateQueryFromSearchAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/CreateQueryFromSearchAction.java
index 52c92d74e..9588af990 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/CreateQueryFromSearchAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/CreateQueryFromSearchAction.java
@@ -13,12 +13,12 @@ import org.eclipse.jface.dialogs.InputDialog;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.window.Window;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.search.ui.ISearchQuery;
 import org.eclipse.search.ui.NewSearchUI;
@@ -57,9 +57,9 @@ public class CreateQueryFromSearchAction extends Action {
 		ISelection selection = resultView.getViewer().getSelection();
 		if (selection instanceof IStructuredSelection) {
 			IStructuredSelection structuredSelection = (IStructuredSelection) selection;
-			if (structuredSelection.getFirstElement() instanceof AbstractTask) {
+			if (structuredSelection.getFirstElement() instanceof ITask) {
 				ISearchQuery[] queries = NewSearchUI.getQueries();
-				AbstractTask task = (AbstractTask) structuredSelection.getFirstElement();
+				ITask task = (ITask) structuredSelection.getFirstElement();
 				AbstractLegacyRepositoryConnector connector = (AbstractLegacyRepositoryConnector) TasksUi.getRepositoryManager()
 						.getRepositoryConnector(task.getConnectorKind());
 				if (queries.length != 0 && connector != null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/OpenSearchResultAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/OpenSearchResultAction.java
index 1901d31bf..d2c284c52 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/OpenSearchResultAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/OpenSearchResultAction.java
@@ -12,7 +12,7 @@ import java.util.Iterator;
 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 
 /**
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/RepositorySearchResultView.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/RepositorySearchResultView.java
index f2c587f03..5089fa1f9 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/RepositorySearchResultView.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/RepositorySearchResultView.java
@@ -25,6 +25,8 @@ import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerFilter;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskGroup;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.AddExistingTaskJob;
@@ -35,8 +37,7 @@ import org.eclipse.mylyn.internal.tasks.ui.actions.OpenTaskSearchAction;
 import org.eclipse.mylyn.internal.tasks.ui.search.SearchResultTreeContentProvider.GroupBy;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListToolTip;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListView;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
@@ -184,8 +185,8 @@ public class RepositorySearchResultView extends AbstractTextSearchViewPage imple
 		new FilteringAction("Filter Completed Tasks", new ViewerFilter() {
 			@Override
 			public boolean select(Viewer viewer, Object parentElement, Object element) {
-				if (element instanceof AbstractTask) {
-					return !((AbstractTask) element).isCompleted();
+				if (element instanceof ITask) {
+					return !((ITask) element).isCompleted();
 				} else if (element instanceof TaskGroup) {
 					TaskGroup taskGroup = (TaskGroup) element;
 					return taskGroup.getHandleIdentifier().equals("group-incompleteIncomplete");
@@ -402,8 +403,8 @@ public class RepositorySearchResultView extends AbstractTextSearchViewPage imple
 		StructuredSelection selection = (StructuredSelection) this.getViewer().getSelection();
 		for (Iterator<?> iterator = selection.iterator(); iterator.hasNext();) {
 			Object selectedObject = iterator.next();
-			if (selectedObject instanceof AbstractTask) {
-				AbstractTask task = (AbstractTask) selectedObject;
+			if (selectedObject instanceof ITask) {
+				ITask task = (ITask) selectedObject;
 				TaskRepository repository = TasksUi.getRepositoryManager().getRepository(task.getConnectorKind(),
 						task.getRepositoryUrl());
 				final AddExistingTaskJob job = new AddExistingTaskJob(repository, task.getTaskId(), category);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchHitCollector.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchHitCollector.java
index 58312764e..51220d4fd 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchHitCollector.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchHitCollector.java
@@ -15,14 +15,14 @@ import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.core.runtime.OperationCanceledException;
 import org.eclipse.core.runtime.Status;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.LegacyTaskDataCollector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterDescription.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterDescription.java
index 51850f709..f15ee8240 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterDescription.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterDescription.java
@@ -10,9 +10,10 @@ package org.eclipse.mylyn.internal.tasks.ui.search;
 
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerSorter;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskKeyComparator;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListTableSorter;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * Sorts search results by summary.
@@ -62,7 +63,7 @@ public class SearchResultSorterDescription extends ViewerSorter {
 	@Override
 	public int category(Object element) {
 		try {
-			AbstractTask hit = (AbstractTask) element;
+			ITask hit = (ITask) element;
 			return Integer.parseInt(hit.getTaskId());
 		} catch (Exception ignored) {
 			// ignore if
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterId.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterId.java
index f8dcf9687..7ec60e39a 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterId.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterId.java
@@ -10,7 +10,7 @@ package org.eclipse.mylyn.internal.tasks.ui.search;
 
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerSorter;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * Sorts search results (AbstractQueryHit) by taskId.
@@ -29,11 +29,11 @@ public class SearchResultSorterId extends ViewerSorter {
 	public int compare(Viewer viewer, Object e1, Object e2) {
 		try {
 			// cast the object and get its bug taskId
-			AbstractTask entry1 = (AbstractTask) e1;
+			ITask entry1 = (ITask) e1;
 			Integer id1 = Integer.parseInt(entry1.getTaskId());
 
 			// cast the other object and get its bug taskId
-			AbstractTask entry2 = (AbstractTask) e2;
+			ITask entry2 = (ITask) e2;
 			Integer id2 = Integer.parseInt(entry2.getTaskId());
 
 			// if neither is null, compare the bug taskId's
@@ -59,7 +59,7 @@ public class SearchResultSorterId extends ViewerSorter {
 	@Override
 	public int category(Object element) {
 		try {
-			AbstractTask hit = (AbstractTask) element;
+			ITask hit = (ITask) element;
 			return Integer.parseInt(hit.getTaskId());
 		} catch (Exception ignored) {
 			// ignore
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterPriority.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterPriority.java
index 22a784e6b..7993bd390 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterPriority.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultSorterPriority.java
@@ -10,7 +10,7 @@ package org.eclipse.mylyn.internal.tasks.ui.search;
 
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerSorter;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 
 /**
  * Sorts results of Bugzilla search by bug priority.
@@ -30,8 +30,8 @@ public class SearchResultSorterPriority extends ViewerSorter {
 	@Override
 	public int compare(Viewer viewer, Object e1, Object e2) {
 		try {
-			AbstractTask hit1 = (AbstractTask) e1;
-			AbstractTask hit2 = (AbstractTask) e2;
+			ITask hit1 = (ITask) e1;
+			ITask hit2 = (ITask) e2;
 			return hit1.getPriority().compareTo(hit2.getPriority());
 		} catch (Exception ignored) {
 			// do nothing
@@ -51,7 +51,7 @@ public class SearchResultSorterPriority extends ViewerSorter {
 	@Override
 	public int category(Object element) {
 		try {
-			AbstractTask hit = (AbstractTask) element;
+			ITask hit = (ITask) element;
 			return Integer.parseInt(hit.getTaskId());
 		} catch (Exception ignored) {
 			// ignore if there is a problem
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultTreeContentProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultTreeContentProvider.java
index 75ff75a84..114262bb5 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultTreeContentProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchResultTreeContentProvider.java
@@ -14,10 +14,11 @@ import java.util.List;
 import java.util.Map;
 
 import org.eclipse.jface.viewers.Viewer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.Person;
 import org.eclipse.mylyn.internal.tasks.core.TaskGroup;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * This implementation of <code>SearchResultContentProvider</code> is used for the table view of a Bugzilla search
@@ -72,7 +73,7 @@ public class SearchResultTreeContentProvider extends SearchResultContentProvider
 
 	public Object[] getChildren(Object parent) {
 		if (parent instanceof TaskGroup || parent instanceof Person) {
-			return ((AbstractTaskContainer) parent).getChildren().toArray();
+			return ((ITaskElement) parent).getChildren().toArray();
 		} else {
 			return EMPTY_ARR;
 		}
@@ -91,7 +92,7 @@ public class SearchResultTreeContentProvider extends SearchResultContentProvider
 		for (Object object : updatedElements) {
 			elements.add(object);
 
-			if (object instanceof AbstractTask) {
+			if (object instanceof ITask) {
 				AbstractTask task = ((AbstractTask) object);
 				String owner = task.getOwner();
 				if (owner == null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchScoreComputerAdapterFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchScoreComputerAdapterFactory.java
index 138d89691..4442dfef4 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchScoreComputerAdapterFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/search/SearchScoreComputerAdapterFactory.java
@@ -9,8 +9,9 @@
 package org.eclipse.mylyn.internal.tasks.ui.search;
 
 import org.eclipse.core.runtime.IAdapterFactory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.TaskSearchPage;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.search.ui.ISearchPageScoreComputer;
 
 /**
@@ -27,7 +28,7 @@ public class SearchScoreComputerAdapterFactory implements IAdapterFactory {
 			if (!TaskSearchPage.ID.equals(pageId)) {
 				return ISearchPageScoreComputer.UNKNOWN;
 			}
-			if (input instanceof AbstractTaskContainer) {
+			if (input instanceof ITaskElement) {
 				return 100;
 			}
 			return ISearchPageScoreComputer.LOWEST;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/DelegatingTaskExternalizer.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/DelegatingTaskExternalizer.java
index 946a74538..f14e72dba 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/DelegatingTaskExternalizer.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/DelegatingTaskExternalizer.java
@@ -22,19 +22,21 @@ import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.commons.core.XmlStringConverter;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.RepositoryTaskHandleUtil;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskExternalizationException;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.internal.tasks.core.UncategorizedTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.tasks.core.AbstractTaskListFactory;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.Node;
@@ -145,14 +147,14 @@ final class DelegatingTaskExternalizer {
 		this.factories = externalizers;
 	}
 
-	public Element createCategoryElement(AbstractTaskContainer category, Document doc, Element parent) {
+	public Element createCategoryElement(ITaskElement category, Document doc, Element parent) {
 		if (category instanceof UncategorizedTaskContainer) {
 			return parent;
 		} else {
 			Element node = doc.createElement(getCategoryTagName());
 			node.setAttribute(DelegatingTaskExternalizer.KEY_NAME, category.getSummary());
 			parent.appendChild(node);
-			for (AbstractTask task : category.getChildren()) {
+			for (ITask task : category.getChildren()) {
 				createTaskReference(KEY_TASK_REFERENCE, task, doc, node);
 			}
 			return node;
@@ -183,7 +185,7 @@ final class DelegatingTaskExternalizer {
 		node.setAttribute(KEY_REPOSITORY_URL, task.getRepositoryUrl());
 
 		//**** TODO API 3.0 to be removed
-		AbstractTaskContainer container = TaskCategory.getParentTaskCategory(task);
+		ITaskElement container = TaskCategory.getParentTaskCategory(task);
 		if (container != null) {
 			if (container.getHandleIdentifier().equals(UncategorizedTaskContainer.HANDLE)) {
 				node.setAttribute(KEY_CATEGORY, VAL_ROOT);
@@ -232,7 +234,7 @@ final class DelegatingTaskExternalizer {
 			node.setAttribute(KEY_MARK_READ_PENDING, VAL_FALSE);
 		}
 
-		AbstractTask abstractTask = task;
+		ITask abstractTask = task;
 		if (abstractTask.getLastReadTimeStamp() != null) {
 			node.setAttribute(KEY_LAST_MOD_DATE, abstractTask.getLastReadTimeStamp());
 		}
@@ -253,7 +255,7 @@ final class DelegatingTaskExternalizer {
 			node.setAttribute(KEY_OWNER, abstractTask.getOwner());
 		}
 
-		for (AbstractTask t : task.getChildren()) {
+		for (ITask t : task.getChildren()) {
 			createTaskReference(KEY_SUBTASK, t, doc, node);
 		}
 
@@ -266,7 +268,7 @@ final class DelegatingTaskExternalizer {
 	 * 
 	 * @return
 	 */
-	public Element createTaskReference(String nodeName, AbstractTask task, Document doc, Element parent) {
+	public Element createTaskReference(String nodeName, ITask task, Document doc, Element parent) {
 		Element node = doc.createElement(nodeName);
 		node.setAttribute(KEY_HANDLE, task.getHandleIdentifier());
 		parent.appendChild(node);
@@ -338,7 +340,7 @@ final class DelegatingTaskExternalizer {
 		readTaskReferences(category, list, taskList);
 	}
 
-	public final AbstractTask readTask(Node node, AbstractTaskCategory legacyCategory, AbstractTask parent)
+	public final AbstractTask readTask(Node node, AbstractTaskCategory legacyCategory, ITask parent)
 			throws TaskExternalizationException {
 		AbstractTask task = null;
 		String taskId = null;
@@ -376,7 +378,7 @@ final class DelegatingTaskExternalizer {
 		return task;
 	}
 
-	private void readTaskInfo(AbstractTask task, Element element, AbstractTask parent,
+	private void readTaskInfo(AbstractTask task, Element element, ITask parent,
 			AbstractTaskCategory legacyCategory) throws TaskExternalizationException {
 		if (task == null) {
 			return;
@@ -562,7 +564,7 @@ final class DelegatingTaskExternalizer {
 		if (query.getLastSynchronizedTimeStamp() != null) {
 			node.setAttribute(DelegatingTaskExternalizer.KEY_LAST_REFRESH, query.getLastSynchronizedTimeStamp());
 		}
-		for (AbstractTask hit : query.getChildren()) {
+		for (ITask hit : query.getChildren()) {
 			try {
 				createTaskReference(KEY_QUERY_HIT, hit, doc, node);
 			} catch (Exception e) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDataExportOperation.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDataExportOperation.java
index 638b00ade..23523b4ca 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDataExportOperation.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDataExportOperation.java
@@ -30,10 +30,11 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.context.core.IInteractionContextManager;
 import org.eclipse.mylyn.internal.commons.core.ZipFileUtil;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.TaskRepositoryManager;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
 /**
@@ -200,7 +201,7 @@ public class TaskDataExportOperation implements IRunnableWithProgress {
 			if (exportTaskContexts) {
 				// Prevent many repeated error messages
 				boolean errorDisplayed = false;
-				for (AbstractTask task : tasks) {
+				for (ITask task : tasks) {
 
 					if (!ContextCore.getContextManager().hasContext(task.getHandleIdentifier())) {
 						continue; // Tasks without a context have no file to
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDragSourceListener.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDragSourceListener.java
index d492289a6..d7db4ddcf 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDragSourceListener.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskDragSourceListener.java
@@ -21,15 +21,16 @@ import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.ISelectionProvider;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.ui.TaskTransfer;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.actions.CopyTaskDetailsAction;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.dnd.DragSourceAdapter;
 import org.eclipse.swt.dnd.DragSourceEvent;
@@ -79,7 +80,7 @@ public class TaskDragSourceListener extends DragSourceAdapter {
 			Object element = it.next();
 			if (element instanceof AbstractRepositoryQuery) {
 				queries.add((AbstractRepositoryQuery) element);
-			} else if (element instanceof AbstractTask) {
+			} else if (element instanceof ITask) {
 				tasks.add((AbstractTask) element);
 			}
 		}
@@ -122,8 +123,8 @@ public class TaskDragSourceListener extends DragSourceAdapter {
 		if (TaskTransfer.getInstance().isSupportedType(event.dataType)) {
 			List<AbstractTask> tasks = new ArrayList<AbstractTask>();
 			for (Iterator<?> it = selection.iterator(); it.hasNext();) {
-				AbstractTaskContainer element = (AbstractTaskContainer) it.next();
-				if (element instanceof AbstractTask) {
+				ITaskElement element = (ITaskElement) it.next();
+				if (element instanceof ITask) {
 					tasks.add((AbstractTask) element);
 				}
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskListElementImporter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskListElementImporter.java
index 341782e36..b2c853a3b 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskListElementImporter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TaskListElementImporter.java
@@ -46,17 +46,17 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.context.core.ContextCorePlugin;
 import org.eclipse.mylyn.internal.context.core.InteractionContext;
 import org.eclipse.mylyn.internal.context.core.InteractionContextExternalizer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.core.TaskExternalizationException;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.internal.tasks.core.TaskRepositoriesExternalizer;
 import org.eclipse.mylyn.internal.tasks.ui.ITasksUiConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.tasks.core.AbstractTaskListFactory;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.w3c.dom.Document;
@@ -153,7 +153,7 @@ public class TaskListElementImporter {
 		}
 
 		// create the categorie nodes...
-		for (AbstractTaskContainer category : taskList.getCategories()) {
+		for (ITaskElement category : taskList.getCategories()) {
 			delagatingExternalizer.createCategoryElement(category, doc, root);
 		}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TasksUiInternal.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TasksUiInternal.java
index 0ae028d74..574f97215 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TasksUiInternal.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/util/TasksUiInternal.java
@@ -29,12 +29,16 @@ import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.mylyn.commons.core.CoreUtil;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.ITaskJobFactory;
 import org.eclipse.mylyn.internal.tasks.core.LocalRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskDelegate;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskSelection;
 import org.eclipse.mylyn.internal.tasks.ui.ITasksUiConstants;
@@ -47,13 +51,11 @@ import org.eclipse.mylyn.internal.tasks.ui.wizards.NewAttachmentWizardDialog;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewTaskWizard;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.TaskAttachmentWizard;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskAttachmentSource;
 import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
 import org.eclipse.mylyn.tasks.core.sync.SynchronizationJob;
@@ -158,8 +160,8 @@ public class TasksUiInternal {
 		});
 	}
 
-	public static void refreshAndOpenTaskListElement(AbstractTaskContainer element) {
-		if (element instanceof AbstractTask || element instanceof ScheduledTaskDelegate) {
+	public static void refreshAndOpenTaskListElement(ITaskElement element) {
+		if (element instanceof ITask || element instanceof ScheduledTaskDelegate) {
 			final AbstractTask task;
 			if (element instanceof ScheduledTaskDelegate) {
 				task = ((ScheduledTaskDelegate) element).getCorrespondingTask();
@@ -324,7 +326,7 @@ public class TasksUiInternal {
 	 * @param listener
 	 * 		can be null
 	 */
-	public static Job synchronizeTask(AbstractRepositoryConnector connector, AbstractTask task, boolean force,
+	public static Job synchronizeTask(AbstractRepositoryConnector connector, ITask task, boolean force,
 			IJobChangeListener listener) {
 		return synchronizeTasks(connector, Collections.singleton(task), force, listener);
 	}
@@ -333,10 +335,10 @@ public class TasksUiInternal {
 	 * @param listener
 	 * 		can be null
 	 */
-	public static Job synchronizeTasks(AbstractRepositoryConnector connector, Set<AbstractTask> tasks, boolean force,
+	public static Job synchronizeTasks(AbstractRepositoryConnector connector, Set<ITask> tasks, boolean force,
 			IJobChangeListener listener) {
 		ITaskList taskList = TasksUi.getTaskList();
-		for (AbstractTask task : tasks) {
+		for (ITask task : tasks) {
 			task.setSynchronizing(true);
 			taskList.notifyTaskChanged(task, false);
 		}
@@ -349,7 +351,7 @@ public class TasksUiInternal {
 			job.addJobChangeListener(listener);
 		}
 		if (force && tasks.size() == 1) {
-			final AbstractTask task = tasks.iterator().next();
+			final ITask task = tasks.iterator().next();
 			job.addJobChangeListener(new JobChangeAdapter() {
 				@Override
 				public void done(IJobChangeEvent event) {
@@ -373,8 +375,7 @@ public class TasksUiInternal {
 	}
 
 	public static NewAttachmentWizardDialog openNewAttachmentWizard(Shell shell, TaskRepository taskRepository,
-			AbstractTask task, TaskAttribute taskAttribute, TaskAttachmentWizard.Mode mode,
-			AbstractTaskAttachmentSource source) {
+			ITask task, TaskAttribute taskAttribute, TaskAttachmentWizard.Mode mode, AbstractTaskAttachmentSource source) {
 		TaskAttachmentWizard attachmentWizard = new TaskAttachmentWizard(taskRepository, task, taskAttribute);
 		attachmentWizard.setSource(source);
 		attachmentWizard.setMode(mode);
@@ -448,8 +449,8 @@ public class TasksUiInternal {
 		}
 		if (selectedObject instanceof TaskCategory) {
 			taskList.addTask(newTask, (TaskCategory) selectedObject);
-		} else if (selectedObject instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) selectedObject;
+		} else if (selectedObject instanceof ITask) {
+			ITask task = (ITask) selectedObject;
 
 			AbstractTaskContainer container = TaskCategory.getParentTaskCategory(task);
 
@@ -478,7 +479,7 @@ public class TasksUiInternal {
 		for (IWorkingSet workingSet : containers) {
 			IAdaptable[] elements = workingSet.getElements();
 			for (IAdaptable adaptable : elements) {
-				if (adaptable instanceof AbstractTaskContainer) {
+				if (adaptable instanceof ITaskElement) {
 					allTaskContainersInWorkingSets.add(((AbstractTaskContainer) adaptable));
 				}
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/CustomTaskListDecorationDrawer.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/CustomTaskListDecorationDrawer.java
index d061df433..4131db58c 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/CustomTaskListDecorationDrawer.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/CustomTaskListDecorationDrawer.java
@@ -10,15 +10,16 @@ package org.eclipse.mylyn.internal.tasks.ui.views;
 
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.AbstractTaskListFilter;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPreferenceConstants;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Rectangle;
@@ -74,7 +75,7 @@ class CustomTaskListDecorationDrawer implements Listener {
 	public void handleEvent(Event event) {
 		Object data = event.item.getData();
 		Image activationImage = null;
-		if (data instanceof AbstractTask) {
+		if (data instanceof ITask) {
 			AbstractTask task = (AbstractTask) data;
 			if (task.isActive()) {
 				activationImage = taskActive;
@@ -84,15 +85,15 @@ class CustomTaskListDecorationDrawer implements Listener {
 				activationImage = taskInactive;
 			}
 		}
-		if (data instanceof AbstractTaskContainer) {
+		if (data instanceof ITaskElement) {
 			switch (event.type) {
 			case SWT.EraseItem: {
 				if (activationImage != null) {
 					drawActivationImage(activationImageOffset, event, activationImage);
 				}
 				if (!this.taskListView.synchronizationOverlaid) {
-					if (data instanceof AbstractTaskContainer) {
-						drawSyncronizationImage((AbstractTaskContainer) data, event);
+					if (data instanceof ITaskElement) {
+						drawSyncronizationImage((ITaskElement) data, event);
 					}
 				}
 
@@ -119,8 +120,8 @@ class CustomTaskListDecorationDrawer implements Listener {
 				if (activationImage != null) {
 					drawActivationImage(activationImageOffset, event, activationImage);
 				}
-				if (data instanceof AbstractTaskContainer) {
-					drawSyncronizationImage((AbstractTaskContainer) data, event);
+				if (data instanceof ITaskElement) {
+					drawSyncronizationImage((ITaskElement) data, event);
 				}
 				if (tweakClipping) {
 					event.gc.setClipping(clipping);
@@ -131,7 +132,7 @@ class CustomTaskListDecorationDrawer implements Listener {
 		}
 	}
 
-	private void drawSyncronizationImage(AbstractTaskContainer element, Event event) {
+	private void drawSyncronizationImage(ITaskElement element, Event event) {
 		Image image = null;
 		int offsetX = 6;
 		int offsetY = (event.height / 2) - 5;
@@ -140,7 +141,7 @@ class CustomTaskListDecorationDrawer implements Listener {
 			offsetY += 2;
 		}
 		if (element != null) {
-			if (element instanceof AbstractTask) {
+			if (element instanceof ITask) {
 				image = CommonImages.getImage(TaskElementLabelProvider.getSynchronizationImageDescriptor(element,
 						taskListView.synchronizationOverlaid));
 			} else {
@@ -183,7 +184,7 @@ class CustomTaskListDecorationDrawer implements Listener {
 		}
 	}
 
-	private boolean hideDecorationOnContainer(AbstractTaskContainer element, TreeItem treeItem) {
+	private boolean hideDecorationOnContainer(ITaskElement element, TreeItem treeItem) {
 		if (element instanceof UnmatchedTaskContainer) {
 			if (!taskListView.isFocusedMode()) {
 				return false;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/DelayedRefreshJob.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/DelayedRefreshJob.java
index 2fc7d439c..6c066561f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/DelayedRefreshJob.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/DelayedRefreshJob.java
@@ -22,7 +22,7 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker;
 import org.eclipse.mylyn.internal.tasks.ui.util.TreeWalker.TreeVisitor;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.swt.SWTException;
 import org.eclipse.swt.widgets.TreeItem;
 import org.eclipse.ui.progress.WorkbenchJob;
@@ -122,8 +122,8 @@ abstract class DelayedRefreshJob extends WorkbenchJob {
 		} else if (items.length > 0) {
 			try {
 				for (Object item : items) {
-					if (item instanceof AbstractTask) {
-						AbstractTask task = (AbstractTask) item;
+					if (item instanceof ITask) {
+						ITask task = (ITask) item;
 						treeViewer.refresh(task, true);
 					} else {
 						treeViewer.refresh(item, true);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/PriorityDropDownAction.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/PriorityDropDownAction.java
index b47d1029f..8d6f5ab4a 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/PriorityDropDownAction.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/PriorityDropDownAction.java
@@ -12,9 +12,9 @@ import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.ActionContributionItem;
 import org.eclipse.jface.action.IMenuCreator;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPreferenceConstants;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Menu;
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TableDecoratingLabelProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TableDecoratingLabelProvider.java
index aef51b3b4..bf1768754 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TableDecoratingLabelProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TableDecoratingLabelProvider.java
@@ -14,10 +14,11 @@ import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ITableLabelProvider;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.graphics.Image;
 
 /**
@@ -30,14 +31,14 @@ public class TableDecoratingLabelProvider extends DecoratingLabelProvider implem
 	}
 
 	public Image getColumnImage(Object element, int columnIndex) {
-		if (!(element instanceof AbstractTaskContainer)) {
+		if (!(element instanceof ITaskElement)) {
 			return null;
 		}
 		if (columnIndex == 0) {
-			if (element instanceof AbstractTaskContainer && !(element instanceof AbstractTask)) {
+			if (element instanceof ITaskElement && !(element instanceof ITask)) {
 				return super.getImage(element);
 			} else {
-				AbstractTask task = TaskElementLabelProvider.getCorrespondingTask((AbstractTaskContainer) element);
+				AbstractTask task = TaskElementLabelProvider.getCorrespondingTask((ITaskElement) element);
 				if (task != null) {
 					if (task.isActive()) {
 						return CommonImages.getImage(TasksUiImages.CONTEXT_ACTIVE);
@@ -53,7 +54,7 @@ public class TableDecoratingLabelProvider extends DecoratingLabelProvider implem
 				}
 			}
 		} else if (columnIndex == 1) {
-			if (element instanceof AbstractTaskContainer || element instanceof AbstractRepositoryQuery) {
+			if (element instanceof ITaskElement || element instanceof AbstractRepositoryQuery) {
 				return null;
 			}
 			return super.getImage(element);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskActivityLabelProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskActivityLabelProvider.java
index 09af90d2b..b54c8ab1d 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskActivityLabelProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskActivityLabelProvider.java
@@ -24,11 +24,11 @@ import org.eclipse.mylyn.internal.provisional.commons.ui.CommonFonts;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskDelegate;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityManager;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.Image;
@@ -78,7 +78,7 @@ public class TaskActivityLabelProvider extends TaskElementLabelProvider implemen
 	public String getColumnText(Object element, int columnIndex) {
 		if (element instanceof ScheduledTaskDelegate) {
 			ScheduledTaskDelegate activityDelegate = (ScheduledTaskDelegate) element;
-			AbstractTask task = activityDelegate.getCorrespondingTask();
+			ITask task = activityDelegate.getCorrespondingTask();
 			switch (columnIndex) {
 			case 2:
 				if (task != null) {
@@ -138,8 +138,8 @@ public class TaskActivityLabelProvider extends TaskElementLabelProvider implemen
 			case 4:
 				long estimated = 0;
 				for (Object o : contentProvider.getChildren(taskCategory)) {
-					if (o instanceof AbstractTask) {
-						estimated += ((AbstractTask) o).getEstimatedTimeHours();
+					if (o instanceof ITask) {
+						estimated += ((ITask) o).getEstimatedTimeHours();
 					}
 				}
 				return estimated + UNITS_HOURS;
@@ -150,7 +150,7 @@ public class TaskActivityLabelProvider extends TaskElementLabelProvider implemen
 
 	@Override
 	public Color getBackground(Object element) {
-		if (element instanceof AbstractTaskContainer && !(element instanceof AbstractTask)) {
+		if (element instanceof ITaskElement && !(element instanceof ITask)) {
 			return categoryBackgroundColor;
 		} else {
 			return super.getBackground(element);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskDetailLabelProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskDetailLabelProvider.java
index 0632dedff..92cec544c 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskDetailLabelProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskDetailLabelProvider.java
@@ -12,10 +12,11 @@ import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.graphics.Image;
@@ -29,12 +30,12 @@ public class TaskDetailLabelProvider extends LabelProvider implements ILabelProv
 
 	@Override
 	public Image getImage(Object element) {
-		if (!(element instanceof AbstractTask)) {
+		if (!(element instanceof ITask)) {
 			return super.getImage(element);
 		}
 
 		AbstractRepositoryConnector connector = TasksUi.getRepositoryManager().getRepositoryConnector(
-				((AbstractTask) element).getConnectorKind());
+				((ITask) element).getConnectorKind());
 		ImageDescriptor overlay = TasksUiPlugin.getDefault().getOverlayIcon(connector.getConnectorKind());
 		if (overlay != null) {
 			return CommonImages.getImageWithOverlay(TasksUiImages.REPOSITORY, overlay, false, false);
@@ -45,11 +46,11 @@ public class TaskDetailLabelProvider extends LabelProvider implements ILabelProv
 
 	@Override
 	public String getText(Object element) {
-		if (!(element instanceof AbstractTask)) {
+		if (!(element instanceof ITask)) {
 			return super.getText(element);
 		}
 
-		AbstractTask task = (AbstractTask) element;
+		ITask task = (ITask) element;
 		TaskRepository repository = TasksUi.getRepositoryManager().getRepository(task.getConnectorKind(),
 				task.getRepositoryUrl());
 		return repository.getRepositoryLabel();
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskElementLabelProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskElementLabelProvider.java
index a62a610da..4dc968d27 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskElementLabelProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskElementLabelProvider.java
@@ -20,21 +20,22 @@ import org.eclipse.mylyn.internal.provisional.commons.ui.CommonColors;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonFonts;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonThemes;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.Person;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskGroup;
 import org.eclipse.mylyn.internal.tasks.core.UncategorizedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.ui.ITaskHighlighter;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.graphics.Color;
@@ -77,13 +78,13 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 	@Override
 	public Image getImage(Object element) {
 		CompositeImageDescriptor compositeDescriptor = getImageDescriptor(element);
-		if (element instanceof AbstractTask) {
+		if (element instanceof ITask) {
 			if (compositeDescriptor.overlayKind == null) {
 				compositeDescriptor.overlayKind = CommonImages.OVERLAY_CLEAR;
 			}
 			return CommonImages.getCompositeTaskImage(compositeDescriptor.icon, compositeDescriptor.overlayKind,
 					wideImages);
-		} else if (element instanceof AbstractTaskContainer) {
+		} else if (element instanceof ITaskElement) {
 			return CommonImages.getCompositeTaskImage(compositeDescriptor.icon, CommonImages.OVERLAY_CLEAR, wideImages);
 		} else {
 			return CommonImages.getCompositeTaskImage(compositeDescriptor.icon, null, wideImages);
@@ -101,13 +102,13 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 			compositeDescriptor.icon = CommonImages.GROUPING;
 		}
 
-		if (object instanceof AbstractTaskContainer) {
-			AbstractTaskContainer element = (AbstractTaskContainer) object;
+		if (object instanceof ITaskElement) {
+			ITaskElement element = (ITaskElement) object;
 
 			AbstractRepositoryConnectorUi connectorUi = null;
-			if (element instanceof AbstractTask) {
-				AbstractTask repositoryTask = (AbstractTask) element;
-				connectorUi = TasksUiPlugin.getConnectorUi(((AbstractTask) element).getConnectorKind());
+			if (element instanceof ITask) {
+				ITask repositoryTask = (ITask) element;
+				connectorUi = TasksUiPlugin.getConnectorUi(((ITask) element).getConnectorKind());
 				if (connectorUi != null) {
 					compositeDescriptor.overlayKind = connectorUi.getTaskKindOverlay(repositoryTask);
 				}
@@ -123,7 +124,7 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 					compositeDescriptor.icon = TasksUiImages.QUERY_UNMATCHED;
 				} else if (element instanceof AbstractRepositoryQuery || object instanceof UnmatchedTaskContainer) {
 					compositeDescriptor.icon = TasksUiImages.QUERY;
-				} else if (element instanceof AbstractTask) {
+				} else if (element instanceof ITask) {
 					compositeDescriptor.icon = TasksUiImages.TASK;
 				} else if (element instanceof ScheduledTaskContainer) {
 					compositeDescriptor.icon = CommonImages.CALENDAR;
@@ -150,8 +151,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 	}
 
 	public static ImageDescriptor getSynchronizationImageDescriptor(Object element, boolean synchViewStyle) {
-		if (element instanceof AbstractTask) {
-			AbstractTask repositoryTask = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask repositoryTask = (ITask) element;
 			if (repositoryTask.getSynchronizationState() == SynchronizationState.INCOMING_NEW) {
 				if (synchViewStyle) {
 					return CommonImages.OVERLAY_SYNC_OLD_INCOMMING_NEW;
@@ -200,15 +201,15 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 
 	public static ImageDescriptor getPriorityImageDescriptor(Object element) {
 		AbstractRepositoryConnectorUi connectorUi;
-		if (element instanceof AbstractTask) {
-			AbstractTask repositoryTask = (AbstractTask) element;
-			connectorUi = TasksUiPlugin.getConnectorUi(((AbstractTask) element).getConnectorKind());
+		if (element instanceof ITask) {
+			ITask repositoryTask = (ITask) element;
+			connectorUi = TasksUiPlugin.getConnectorUi(((ITask) element).getConnectorKind());
 			if (connectorUi != null) {
 				return connectorUi.getTaskPriorityOverlay(repositoryTask);
 			}
 		}
-		if (element instanceof AbstractTask) {
-			AbstractTask task = TaskElementLabelProvider.getCorrespondingTask((AbstractTaskContainer) element);
+		if (element instanceof ITask) {
+			ITask task = TaskElementLabelProvider.getCorrespondingTask((ITaskElement) element);
 			if (task != null) {
 				return TasksUiImages.getImageDescriptorForPriority(PriorityLevel.fromString(task.getPriority()));
 			}
@@ -218,8 +219,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 
 	@Override
 	public String getText(Object object) {
-		if (object instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) object;
+		if (object instanceof ITask) {
+			ITask task = (ITask) object;
 			if (task.getSummary() == null) {
 				if (task.getTaskKey() != null) {
 					return task.getTaskKey() + NO_SUMMARY_AVAILABLE;
@@ -251,8 +252,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 
 			return result;
 
-		} else if (object instanceof AbstractTaskContainer) {
-			AbstractTaskContainer element = (AbstractTaskContainer) object;
+		} else if (object instanceof ITaskElement) {
+			ITaskElement element = (ITaskElement) object;
 			return element.getSummary();
 		} else {
 			return super.getText(object);
@@ -260,8 +261,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 	}
 
 	public Color getForeground(Object object) {
-		if (object instanceof AbstractTaskContainer && object instanceof AbstractTask) {
-			AbstractTask task = getCorrespondingTask((AbstractTaskContainer) object);
+		if (object instanceof ITaskElement && object instanceof ITask) {
+			AbstractTask task = getCorrespondingTask((ITaskElement) object);
 			if (task != null) {
 				if (TasksUiPlugin.getTaskActivityManager().isCompletedToday(task)) {
 					return themeManager.getCurrentTheme().getColorRegistry().get(CommonThemes.COLOR_COMPLETED_TODAY);
@@ -283,8 +284,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 							.get(CommonThemes.COLOR_SCHEDULED_THIS_WEEK);
 				}
 			}
-		} else if (object instanceof AbstractTaskContainer) {
-			for (AbstractTask child : ((AbstractTaskContainer) object).getChildren()) {
+		} else if (object instanceof ITaskElement) {
+			for (ITask child : ((ITaskElement) object).getChildren()) {
 				if (child.isActive() || showHasActiveChild(child)) {
 					return CommonColors.CONTEXT_ACTIVE;
 				} else if (TasksUiPlugin.getTaskActivityManager().isOverdue(child)) {
@@ -321,8 +322,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 	/**
 	 * TODO: move
 	 */
-	public static AbstractTask getCorrespondingTask(AbstractTaskContainer element) {
-		if (element instanceof AbstractTask) {
+	public static AbstractTask getCorrespondingTask(ITaskElement element) {
+		if (element instanceof ITask) {
 			return (AbstractTask) element;
 		} else {
 			return null;
@@ -330,8 +331,8 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 	}
 
 	public Color getBackground(Object element) {
-		if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask task = (ITask) element;
 			ITaskHighlighter highlighter = TasksUiPlugin.getDefault().getHighlighter();
 			if (highlighter != null) {
 				return highlighter.getHighlightColor(task);
@@ -341,24 +342,24 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 	}
 
 	public Font getFont(Object element) {
-		if (!(element instanceof AbstractTaskContainer)) {
+		if (!(element instanceof ITaskElement)) {
 			return null;
 		}
-		AbstractTask task = getCorrespondingTask((AbstractTaskContainer) element);
+		AbstractTask task = getCorrespondingTask((ITaskElement) element);
 		if (task != null) {
-			AbstractTask repositoryTask = task;
+			ITask repositoryTask = task;
 			if (repositoryTask.isSynchronizing()) {
 				return CommonFonts.ITALIC;
 			}
 		}
-		if (element instanceof AbstractTaskContainer) {
+		if (element instanceof ITaskElement) {
 			if (element instanceof AbstractRepositoryQuery) {
 				if (((AbstractRepositoryQuery) element).isSynchronizing()) {
 					return CommonFonts.ITALIC;
 				}
 			}
 
-			for (AbstractTask child : ((AbstractTaskContainer) element).getChildren()) {
+			for (ITask child : ((ITaskElement) element).getChildren()) {
 				if (child.isActive() || showHasActiveChild(child)) {
 					return CommonFonts.BOLD;
 				}
@@ -370,7 +371,7 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 			} else if (task.isCompleted()) {
 				return CommonFonts.STRIKETHROUGH;
 			}
-			for (AbstractTask child : ((AbstractTaskContainer) element).getChildren()) {
+			for (ITask child : ((ITaskElement) element).getChildren()) {
 				if (child.isActive() || showHasActiveChild(child)) {
 					return CommonFonts.BOLD;
 				}
@@ -379,22 +380,21 @@ public class TaskElementLabelProvider extends LabelProvider implements IColorPro
 		return null;
 	}
 
-	private boolean showHasActiveChild(AbstractTaskContainer container) {
+	private boolean showHasActiveChild(ITaskElement container) {
 		if (!TasksUiPlugin.getDefault().groupSubtasks(container)) {
 			return false;
 		}
 
-		return showHasActiveChildHelper(container, new HashSet<AbstractTaskContainer>());
+		return showHasActiveChildHelper(container, new HashSet<ITaskElement>());
 	}
 
-	private boolean showHasActiveChildHelper(AbstractTaskContainer container,
-			Set<AbstractTaskContainer> visitedContainers) {
-		for (AbstractTaskContainer child : container.getChildren()) {
+	private boolean showHasActiveChildHelper(ITaskElement container, Set<ITaskElement> visitedContainers) {
+		for (ITaskElement child : container.getChildren()) {
 			if (visitedContainers.contains(child)) {
 				continue;
 			}
 			visitedContainers.add(child);
-			if (child instanceof AbstractTask && ((AbstractTask) child).isActive()) {
+			if (child instanceof ITask && ((AbstractTask) child).isActive()) {
 				return true;
 			} else {
 				if (showHasActiveChildHelper(child, visitedContainers)) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListCellModifier.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListCellModifier.java
index 26e3b90dd..71d3c49ed 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListCellModifier.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListCellModifier.java
@@ -14,13 +14,15 @@ import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.jface.viewers.ICellModifier;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskActivateAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskDeactivateAction;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.widgets.TreeItem;
 
@@ -48,8 +50,8 @@ class TaskListCellModifier implements ICellModifier {
 	public Object getValue(Object element, String property) {
 		try {
 			int columnIndex = Arrays.asList(this.taskListView.columnNames).indexOf(property);
-			if (element instanceof AbstractTaskContainer) {
-				final AbstractTaskContainer taskListElement = (AbstractTaskContainer) element;
+			if (element instanceof ITaskElement) {
+				final ITaskElement taskListElement = (ITaskElement) element;
 				switch (columnIndex) {
 				case 0:
 					return taskListElement.getSummary();
@@ -72,8 +74,8 @@ class TaskListCellModifier implements ICellModifier {
 				return;
 			}
 			columnIndex = Arrays.asList(this.taskListView.columnNames).indexOf(property);
-			if (((TreeItem) element).getData() instanceof AbstractTask) {
-				final AbstractTaskContainer taskListElement = (AbstractTaskContainer) ((TreeItem) element).getData();
+			if (((TreeItem) element).getData() instanceof ITask) {
+				final ITaskElement taskListElement = (ITaskElement) ((TreeItem) element).getData();
 				AbstractTask task = (AbstractTask) taskListElement;
 				switch (columnIndex) {
 				case 0:
@@ -109,10 +111,10 @@ class TaskListCellModifier implements ICellModifier {
 	}
 
 	public void toggleTaskActivation(TreeItem element) {
-		AbstractTaskContainer taskListElement = (AbstractTaskContainer) element.getData();
+		ITaskElement taskListElement = (ITaskElement) element.getData();
 
 		AbstractTask task = null;
-		if (taskListElement instanceof AbstractTask) {
+		if (taskListElement instanceof ITask) {
 			task = (AbstractTask) taskListElement;
 		}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListContentProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListContentProvider.java
index edd827865..acbca05ad 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListContentProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListContentProvider.java
@@ -17,12 +17,14 @@ import java.util.List;
 import java.util.Set;
 
 import org.eclipse.jface.viewers.Viewer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.AbstractTaskListFilter;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * Provides custom content for the task list, e.g. guaranteed visibility of some elements, ability to suppress
@@ -58,8 +60,8 @@ public class TaskListContentProvider extends AbstractTaskListContentProvider {
 	 */
 	public Object getParent(Object child) {
 		// return first parent found, first search within categories then queries
-		if (child instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) child;
+		if (child instanceof ITask) {
+			ITask task = (ITask) child;
 			AbstractTaskCategory parent = TaskCategory.getParentTaskCategory(task);
 			if (parent != null) {
 				return parent;
@@ -118,7 +120,7 @@ public class TaskListContentProvider extends AbstractTaskListContentProvider {
 		return filterText == null || filterText.length() == 0;
 	}
 
-	private boolean selectContainer(AbstractTaskContainer container) {
+	private boolean selectContainer(ITaskElement container) {
 //		if (container instanceof ScheduledTaskContainer) {
 //			ScheduledTaskContainer scheduleContainer = (ScheduledTaskContainer) container;
 //			if (TasksUiPlugin.getTaskActivityManager().isWeekDay(scheduleContainer)
@@ -135,24 +137,24 @@ public class TaskListContentProvider extends AbstractTaskListContentProvider {
 		return true;
 	}
 
-	private List<AbstractTaskContainer> getFilteredChildrenFor(Object parent) {
+	private List<ITaskElement> getFilteredChildrenFor(Object parent) {
 		if (containsNoFilterText((this.taskListView.getFilteredTree().getFilterControl()).getText())) {
-			List<AbstractTaskContainer> children = new ArrayList<AbstractTaskContainer>();
-			if (parent instanceof AbstractTask) {
-				Collection<AbstractTask> subTasks = ((AbstractTask) parent).getChildren();
-				for (AbstractTask t : subTasks) {
-					if (!filter(parent, t)) {
-						children.add(t);
+			List<ITaskElement> children = new ArrayList<ITaskElement>();
+			if (parent instanceof ITask) {
+				Collection<ITask> subTasks = ((AbstractTask) parent).getChildren();
+				for (ITask task : subTasks) {
+					if (!filter(parent, task)) {
+						children.add(task);
 					}
 				}
 				return children;
-			} else if (parent instanceof AbstractTaskContainer) {
-				return getFilteredRootChildren((AbstractTaskContainer) parent);
+			} else if (parent instanceof ITaskElement) {
+				return getFilteredRootChildren((ITaskElement) parent);
 			}
 		} else {
-			List<AbstractTaskContainer> children = new ArrayList<AbstractTaskContainer>();
-			if (parent instanceof AbstractTaskContainer) {
-				children.addAll(((AbstractTaskContainer) parent).getChildren());
+			List<ITaskElement> children = new ArrayList<ITaskElement>();
+			if (parent instanceof ITaskElement) {
+				children.addAll(((ITaskElement) parent).getChildren());
 				return children;
 			}
 		}
@@ -162,26 +164,26 @@ public class TaskListContentProvider extends AbstractTaskListContentProvider {
 	/**
 	 * @return all children who aren't already revealed as a sub task
 	 */
-	private List<AbstractTaskContainer> getFilteredRootChildren(AbstractTaskContainer parent) {
-		List<AbstractTaskContainer> result = new ArrayList<AbstractTaskContainer>();
+	private List<ITaskElement> getFilteredRootChildren(ITaskElement parent) {
+		List<ITaskElement> result = new ArrayList<ITaskElement>();
 		if (TasksUiPlugin.getDefault().groupSubtasks(parent)) {
-			Collection<AbstractTask> parentTasks = parent.getChildren();
-			Set<AbstractTaskContainer> parents = new HashSet<AbstractTaskContainer>();
-			Set<AbstractTask> children = new HashSet<AbstractTask>();
+			Collection<ITask> parentTasks = parent.getChildren();
+			Set<ITaskElement> parents = new HashSet<ITaskElement>();
+			Set<ITask> children = new HashSet<ITask>();
 			// get all children
-			for (AbstractTask element : parentTasks) {
-				for (AbstractTask abstractTask : element.getChildren()) {
+			for (ITask element : parentTasks) {
+				for (ITask abstractTask : element.getChildren()) {
 					children.add(abstractTask);
 				}
 			}
-			for (AbstractTask task : parentTasks) {
+			for (ITask task : parentTasks) {
 				if (!filter(parent, task) && !children.contains(task)) {
 					parents.add(task);
 				}
 			}
 			result.addAll(parents);
 		} else {
-			for (AbstractTaskContainer element : parent.getChildren()) {
+			for (ITaskElement element : parent.getChildren()) {
 				if (!filter(parent, element)) {
 					result.add(element);
 				}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListDropAdapter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListDropAdapter.java
index 15ac5b58b..2805f261f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListDropAdapter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListDropAdapter.java
@@ -32,6 +32,9 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.context.core.ContextCorePlugin;
 import org.eclipse.mylyn.internal.context.core.InteractionContext;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityUtil;
@@ -49,10 +52,8 @@ import org.eclipse.mylyn.internal.tasks.ui.actions.TaskActivateAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskImportAction;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
@@ -106,7 +107,7 @@ public class TaskListDropAdapter extends ViewerDropAdapter {
 				if (isUrl(data) && createTaskFromUrl(data)) {
 					tasksToMove.add(newTask);
 				} else if (TaskTransfer.getInstance().isSupportedType(currentTransfer)
-						&& data instanceof AbstractTask[]) {
+						&& data instanceof ITask[]) {
 					AbstractTask[] tasks = (AbstractTask[]) data;
 					for (AbstractTask task : tasks) {
 						if (task != null) {
@@ -117,7 +118,7 @@ public class TaskListDropAdapter extends ViewerDropAdapter {
 					tasksToMove.add(newTask);
 				} else if (FileTransfer.getInstance().isSupportedType(currentTransfer)) {
 					// transfer the context if the target is a Task
-					if (getCurrentTarget() instanceof AbstractTask) {
+					if (getCurrentTarget() instanceof ITask) {
 						AbstractTask targetTask = (AbstractTask) getCurrentTarget();
 						final String[] names = (String[]) data;
 						boolean confirmed = MessageDialog.openConfirm(getViewer().getControl().getShell(),
@@ -208,11 +209,11 @@ public class TaskListDropAdapter extends ViewerDropAdapter {
 								TasksUi.getTaskList().addTask(task,
 										(AbstractTaskCategory) currentTarget);
 							}
-						} else if (currentTarget instanceof AbstractTask) {
-							AbstractTask targetTask = (AbstractTask) currentTarget;
+						} else if (currentTarget instanceof ITask) {
+							ITask targetTask = (ITask) currentTarget;
 							AbstractTaskCategory targetCategory = null;
 							// TODO: TaskCategory only used what about AbstractTaskCategory descendants?
-							AbstractTaskContainer container = TaskCategory.getParentTaskCategory(targetTask);
+							ITaskElement container = TaskCategory.getParentTaskCategory(targetTask);
 							if (container instanceof TaskCategory || container instanceof UncategorizedTaskContainer) {
 								targetCategory = (AbstractTaskCategory) container;
 							} else if (container instanceof UnmatchedTaskContainer) {
@@ -262,7 +263,7 @@ public class TaskListDropAdapter extends ViewerDropAdapter {
 	}
 
 	private boolean areAllLocalTasks(List<AbstractTask> tasksToMove) {
-		for (AbstractTask task : tasksToMove) {
+		for (ITask task : tasksToMove) {
 			if (!(task instanceof LocalTask)) {
 				return false;
 			}
@@ -381,7 +382,7 @@ public class TaskListDropAdapter extends ViewerDropAdapter {
 					|| getCurrentTarget() instanceof UnmatchedTaskContainer
 					|| getCurrentTarget() instanceof ScheduledTaskContainer) {
 				return true;
-			} else if (getCurrentTarget() instanceof AbstractTaskContainer
+			} else if (getCurrentTarget() instanceof ITaskElement
 					&& (getCurrentLocation() == ViewerDropAdapter.LOCATION_AFTER || getCurrentLocation() == ViewerDropAdapter.LOCATION_BEFORE)) {
 				return true;
 			} else if (getCurrentTarget() instanceof LocalTask
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListFilteredTree.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListFilteredTree.java
index 44a1e8d67..37b81c69e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListFilteredTree.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListFilteredTree.java
@@ -26,6 +26,7 @@ import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractFilteredTree;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonColors;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.IDynamicSubMenuContributor;
 import org.eclipse.mylyn.internal.tasks.ui.TaskHistoryDropDown;
 import org.eclipse.mylyn.internal.tasks.ui.TaskListHyperlink;
@@ -39,8 +40,8 @@ import org.eclipse.mylyn.internal.tasks.ui.actions.TaskDeactivateAction;
 import org.eclipse.mylyn.internal.tasks.ui.actions.TaskWorkingSetAction;
 import org.eclipse.mylyn.internal.tasks.ui.editors.TaskListChangeAdapter;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskListChangeListener;
 import org.eclipse.mylyn.tasks.core.TaskActivityAdapter;
 import org.eclipse.mylyn.tasks.core.TaskContainerDelta;
@@ -163,7 +164,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 			@Override
 			public void containersChanged(Set<TaskContainerDelta> containers) {
 				for (TaskContainerDelta taskContainerDelta : containers) {
-					if (taskContainerDelta.getContainer() instanceof AbstractTask) {
+					if (taskContainerDelta.getContainer() instanceof ITask) {
 						updateTaskProgressBar();
 						break;
 					}
@@ -222,13 +223,13 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 			return;
 		}
 
-		Set<AbstractTask> tasksThisWeek = TasksUiPlugin.getTaskActivityManager().getScheduledForThisWeek();
+		Set<ITask> tasksThisWeek = TasksUiPlugin.getTaskActivityManager().getScheduledForThisWeek();
 
 		totalTasks = tasksThisWeek.size();
 		completeTime = 0;
 		completeTasks = 0;
 		incompleteTime = 0;
-		for (AbstractTask task : tasksThisWeek) {
+		for (ITask task : tasksThisWeek) {
 			if (task.isCompleted()) {
 				completeTasks++;
 				if (task.getEstimatedTimeHours() > 0) {
@@ -327,7 +328,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 			@Override
 			public void containersChanged(Set<TaskContainerDelta> containers) {
 				for (TaskContainerDelta taskContainerDelta : containers) {
-					if (taskContainerDelta.getContainer() instanceof AbstractTask) {
+					if (taskContainerDelta.getContainer() instanceof ITask) {
 						final AbstractTask changedTask = (AbstractTask) (taskContainerDelta.getContainer());
 						if (Platform.isRunning() && PlatformUI.getWorkbench() != null && Display.getCurrent() == null) {
 							PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {
@@ -356,7 +357,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 
 		taskListToolTip = new TaskListToolTip(activeTaskLink);
 
-		AbstractTask activeTask = TasksUi.getTaskActivityManager().getActiveTask();
+		ITask activeTask = TasksUi.getTaskActivityManager().getActiveTask();
 		if (activeTask != null) {
 			indicateActiveTask(activeTask);
 		}
@@ -400,7 +401,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 			@Override
 			public void mouseDown(MouseEvent e) {
 				if (e.button == 1) {
-					AbstractTask activeTask = (TasksUi.getTaskActivityManager().getActiveTask());
+					ITask activeTask = (TasksUi.getTaskActivityManager().getActiveTask());
 					if (activeTask == null) {
 						ActivateTaskDialogAction activateAction = new ActivateTaskDialogAction();
 						activateAction.init(PlatformUI.getWorkbench().getActiveWorkbenchWindow());
@@ -457,7 +458,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 		filterComposite.layout();
 	}
 
-	public void indicateActiveTask(AbstractTask task) {
+	public void indicateActiveTask(ITask task) {
 		if (Display.getCurrent() != null) {
 
 			if (filterComposite.isDisposed()) {
@@ -494,7 +495,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 		}
 	}
 
-	private void fillContextMenu(IMenuManager manager, final AbstractTask activeTask) {
+	private void fillContextMenu(IMenuManager manager, final ITask activeTask) {
 		if (activeTask != null) {
 			IStructuredSelection selection = new StructuredSelection(activeTask);
 			copyTaskDetailsAction.selectionChanged(selection);
@@ -529,7 +530,7 @@ public class TaskListFilteredTree extends AbstractFilteredTree {
 				for (IDynamicSubMenuContributor contributor : TasksUiPlugin.getDefault().getDynamicMenuMap().get(
 						menuPath)) {
 					if (TaskListView.ID_SEPARATOR_TASKS.equals(menuPath)) {
-						List<AbstractTaskContainer> selectedElements = new ArrayList<AbstractTaskContainer>();
+						List<ITaskElement> selectedElements = new ArrayList<ITaskElement>();
 						selectedElements.add(activeTask);
 						MenuManager subMenuManager = contributor.getSubMenuManager(selectedElements);
 						if (subMenuManager != null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListTableSorter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListTableSorter.java
index b1aff196f..3cd692f42 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListTableSorter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListTableSorter.java
@@ -11,13 +11,13 @@ package org.eclipse.mylyn.internal.tasks.ui.views;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerSorter;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.UncategorizedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.ITasksUiConstants;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.ui.PlatformUI;
 
 /**
@@ -73,49 +73,49 @@ public class TaskListTableSorter extends ViewerSorter {
 				return -1;
 			}
 			return -1 * dateRangeTaskContainer2.getStart().compareTo(dateRangeTaskContainer1.getStart());
-		} else if (o1 instanceof AbstractTaskContainer && o2 instanceof ScheduledTaskContainer) {
+		} else if (o1 instanceof ITaskElement && o2 instanceof ScheduledTaskContainer) {
 			return -1;
-		} else if (o1 instanceof ScheduledTaskContainer && o2 instanceof AbstractTaskContainer) {
+		} else if (o1 instanceof ScheduledTaskContainer && o2 instanceof ITaskElement) {
 			return 1;
 		}
 
-		if (o1 instanceof AbstractTaskContainer && o2 instanceof UncategorizedTaskContainer) {
+		if (o1 instanceof ITaskElement && o2 instanceof UncategorizedTaskContainer) {
 			return 1;
-		} else if (o2 instanceof AbstractTaskContainer && o1 instanceof UncategorizedTaskContainer) {
+		} else if (o2 instanceof ITaskElement && o1 instanceof UncategorizedTaskContainer) {
 			return -1;
 		}
 
-		if (o1 instanceof AbstractTaskContainer && o2 instanceof UnmatchedTaskContainer) {
+		if (o1 instanceof ITaskElement && o2 instanceof UnmatchedTaskContainer) {
 			return -1;
-		} else if (o2 instanceof AbstractTaskContainer && o1 instanceof UnmatchedTaskContainer) {
+		} else if (o2 instanceof ITaskElement && o1 instanceof UnmatchedTaskContainer) {
 			return 1;
 		}
 
-		if (!(o1 instanceof AbstractTask) && o2 instanceof AbstractTask) {
+		if (!(o1 instanceof ITask) && o2 instanceof ITask) {
 			return 1;
 		}
 
-		if (o1 instanceof AbstractTask && !(o2 instanceof AbstractTaskContainer)) {
+		if (o1 instanceof ITask && !(o2 instanceof ITaskElement)) {
 			return -1;
 		}
 
 		// if (o1 instanceof AbstractTaskContainer || o1 instanceof
 		// AbstractRepositoryQuery) {
-		if (!(o1 instanceof AbstractTask)) {
-			if (o2 instanceof AbstractTaskContainer || o2 instanceof AbstractRepositoryQuery) {
+		if (!(o1 instanceof ITask)) {
+			if (o2 instanceof ITaskElement || o2 instanceof AbstractRepositoryQuery) {
 
 				return this.sortDirection
-						* ((AbstractTaskContainer) o1).getSummary().compareToIgnoreCase(
-								((AbstractTaskContainer) o2).getSummary());
+						* ((ITaskElement) o1).getSummary().compareToIgnoreCase(
+								((ITaskElement) o2).getSummary());
 			} else {
 				return -1;
 			}
-		} else if (o1 instanceof AbstractTaskContainer) {
-			if (!(o2 instanceof AbstractTask)) {
+		} else if (o1 instanceof ITaskElement) {
+			if (!(o2 instanceof ITask)) {
 				return -1;
-			} else if (o2 instanceof AbstractTaskContainer) {
-				AbstractTaskContainer element1 = (AbstractTaskContainer) o1;
-				AbstractTaskContainer element2 = (AbstractTaskContainer) o2;
+			} else if (o2 instanceof ITaskElement) {
+				ITaskElement element1 = (ITaskElement) o1;
+				ITaskElement element2 = (ITaskElement) o2;
 
 				return compareElements(element1, element2);
 			}
@@ -125,7 +125,7 @@ public class TaskListTableSorter extends ViewerSorter {
 		return 0;
 	}
 
-	private int compareElements(AbstractTaskContainer element1, AbstractTaskContainer element2) {
+	private int compareElements(ITaskElement element1, ITaskElement element2) {
 		if (SortByIndex.PRIORITY.equals(sortByIndex)) {
 			int result = this.sortDirection * element1.getPriority().compareTo(element2.getPriority());
 			if (result != 0) {
@@ -134,13 +134,13 @@ public class TaskListTableSorter extends ViewerSorter {
 			return sortBySummary(element1, element2);
 
 		} else if (SortByIndex.DATE_CREATED.equals(sortByIndex)) {
-			AbstractTask t1 = null;
-			AbstractTask t2 = null;
-			if (element1 instanceof AbstractTask) {
-				t1 = (AbstractTask) element1;
+			ITask t1 = null;
+			ITask t2 = null;
+			if (element1 instanceof ITask) {
+				t1 = (ITask) element1;
 			}
-			if (element2 instanceof AbstractTask) {
-				t2 = (AbstractTask) element2;
+			if (element2 instanceof ITask) {
+				t2 = (ITask) element2;
 			}
 			if (t1 != null && t2 != null) {
 				if (t1.getCreationDate() != null) {
@@ -160,7 +160,7 @@ public class TaskListTableSorter extends ViewerSorter {
 	 * @param element2
 	 * @return sort order
 	 */
-	private int sortBySummary(AbstractTaskContainer element1, AbstractTaskContainer element2) {
+	private int sortBySummary(ITaskElement element1, ITaskElement element2) {
 		return this.sortDirection
 				* taskKeyComparator.compare(getSortableFromElement(element1), getSortableFromElement(element2));
 	}
@@ -173,11 +173,11 @@ public class TaskListTableSorter extends ViewerSorter {
 	 * @deprecated Use getSortableFromElement()
 	 */
 	@Deprecated
-	public static String getSortableSummaryFromElement(AbstractTaskContainer element) {
+	public static String getSortableSummaryFromElement(ITaskElement element) {
 		String summary = element.getSummary();
 
-		if (element instanceof AbstractTask) {
-			AbstractTask task1 = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask task1 = (ITask) element;
 			if (task1.getTaskKey() != null) {
 				summary = task1.getTaskKey() + ": " + summary;
 			}
@@ -191,11 +191,11 @@ public class TaskListTableSorter extends ViewerSorter {
 	 * @param element
 	 * @return String array[component, taskId, summary]
 	 */
-	public static String[] getSortableFromElement(AbstractTaskContainer element) {
+	public static String[] getSortableFromElement(ITaskElement element) {
 		final String a[] = new String[] { "", null, element.getSummary() };
 
-		if (element instanceof AbstractTask) {
-			AbstractTask task1 = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask task1 = (ITask) element;
 			if (task1.getTaskKey() != null) {
 				a[1] = task1.getTaskKey();
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListToolTip.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListToolTip.java
index a3fde7bc1..83ed0389d 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListToolTip.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListToolTip.java
@@ -24,6 +24,9 @@ import org.eclipse.jface.window.ToolTip;
 import org.eclipse.mylyn.commons.core.DateUtil;
 import org.eclipse.mylyn.internal.provisional.commons.ui.AbstractNotification;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.UncategorizedTaskContainer;
@@ -34,9 +37,8 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPreferenceConstants;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
@@ -79,7 +81,7 @@ public class TaskListToolTip extends ToolTip {
 
 	private final static int Y_SHIFT = 1;
 
-	private AbstractTaskContainer currentTipElement;
+	private ITaskElement currentTipElement;
 
 	private final List<TaskListToolTipListener> listeners = new ArrayList<TaskListToolTipListener>();
 
@@ -117,24 +119,24 @@ public class TaskListToolTip extends ToolTip {
 		listeners.remove(listener);
 	}
 
-	private AbstractTaskContainer getTaskListElement(Object hoverObject) {
+	private ITaskElement getTaskListElement(Object hoverObject) {
 		if (hoverObject instanceof TaskListHyperlink) {
 			TaskListHyperlink hyperlink = (TaskListHyperlink) hoverObject;
 			return hyperlink.getTask();
 		} else if (hoverObject instanceof Widget) {
 			Object data = ((Widget) hoverObject).getData();
 			if (data != null) {
-				if (data instanceof AbstractTaskContainer) {
-					return (AbstractTaskContainer) data;
+				if (data instanceof ITaskElement) {
+					return (ITaskElement) data;
 				} else if (data instanceof IAdaptable) {
-					return (AbstractTaskContainer) ((IAdaptable) data).getAdapter(AbstractTaskContainer.class);
+					return (ITaskElement) ((IAdaptable) data).getAdapter(AbstractTaskContainer.class);
 				}
 			}
 		}
 		return null;
 	}
 
-	private String getTitleText(AbstractTaskContainer element) {
+	private String getTitleText(ITaskElement element) {
 		if (element instanceof ScheduledTaskContainer) {
 			StringBuilder sb = new StringBuilder();
 			sb.append(element.getSummary());
@@ -156,12 +158,12 @@ public class TaskListToolTip extends ToolTip {
 		}
 	}
 
-	private String getDetailsText(AbstractTaskContainer element) {
+	private String getDetailsText(ITaskElement element) {
 		if (element instanceof ScheduledTaskContainer) {
 			ScheduledTaskContainer container = (ScheduledTaskContainer) element;
 			int estimateTotal = 0;
 			long elapsedTotal = 0;
-			for (AbstractTask child : container.getChildren()) {
+			for (ITask child : container.getChildren()) {
 				estimateTotal += (child).getEstimatedTimeHours();
 				elapsedTotal += TasksUiPlugin.getTaskActivityManager().getElapsedTime(child, container.getStart(),
 						container.getEnd());
@@ -175,8 +177,8 @@ public class TaskListToolTip extends ToolTip {
 			sb.append(DateUtil.getFormattedDurationShort(elapsedTotal));
 			sb.append("\n");
 			return sb.toString();
-		} else if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		} else if (element instanceof ITask) {
+			ITask task = (ITask) element;
 			StringBuilder sb = new StringBuilder();
 			AbstractRepositoryConnectorUi connectorUi = TasksUiPlugin.getConnectorUi(task.getConnectorKind());
 			sb.append(connectorUi.getTaskKindLabel(task));
@@ -209,7 +211,7 @@ public class TaskListToolTip extends ToolTip {
 		return "";
 	}
 
-	private String getActivityText(AbstractTaskContainer element) {
+	private String getActivityText(ITaskElement element) {
 //		if (element instanceof ScheduledTaskDelegate) {
 //			ScheduledTaskDelegate task = (ScheduledTaskDelegate) element;
 //
@@ -232,8 +234,8 @@ public class TaskListToolTip extends ToolTip {
 //			return sb.toString();
 //		} else 
 //			
-		if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask task = (ITask) element;
 
 			StringBuilder sb = new StringBuilder();
 
@@ -266,8 +268,8 @@ public class TaskListToolTip extends ToolTip {
 		return null;
 	}
 
-	private String getIncommingText(AbstractTaskContainer element) {
-		if (element instanceof AbstractTask) {
+	private String getIncommingText(ITaskElement element) {
+		if (element instanceof ITask) {
 			AbstractTask task = (AbstractTask) element;
 			if (task.getSynchronizationState().isIncoming()) {
 				AbstractRepositoryConnector connector = TasksUi.getRepositoryManager().getRepositoryConnector(
@@ -297,10 +299,10 @@ public class TaskListToolTip extends ToolTip {
 		return null;
 	}
 
-	private String getStatusText(AbstractTaskContainer element) {
+	private String getStatusText(ITaskElement element) {
 		IStatus status = null;
-		if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		if (element instanceof ITask) {
+			ITask task = (ITask) element;
 			status = task.getSynchronizationStatus();
 		} else if (element instanceof AbstractRepositoryQuery) {
 			AbstractRepositoryQuery query = (AbstractRepositoryQuery) element;
@@ -331,8 +333,8 @@ public class TaskListToolTip extends ToolTip {
 		return super.getLocation(tipSize, event);//control.toDisplay(event.x + xShift, event.y + yShift);
 	}
 
-	private ProgressData getProgressData(AbstractTaskContainer element) {
-		if (element instanceof AbstractTask) {
+	private ProgressData getProgressData(ITaskElement element) {
+		if (element instanceof ITask) {
 			return null;
 		}
 		Object[] children = new Object[0];
@@ -341,7 +343,7 @@ public class TaskListToolTip extends ToolTip {
 
 		int total = children.length;
 		int completed = 0;
-		for (AbstractTask task : element.getChildren()) {
+		for (ITask task : element.getChildren()) {
 			if (task.isCompleted()) {
 				completed++;
 			}
@@ -351,7 +353,7 @@ public class TaskListToolTip extends ToolTip {
 		return new ProgressData(completed, total, text);
 	}
 
-	private Image getImage(AbstractTaskContainer element) {
+	private Image getImage(ITaskElement element) {
 		if (element instanceof AbstractRepositoryQuery) {
 			AbstractRepositoryQuery query = (AbstractRepositoryQuery) element;
 			AbstractRepositoryConnector connector = TasksUi.getRepositoryManager().getRepositoryConnector(
@@ -359,8 +361,8 @@ public class TaskListToolTip extends ToolTip {
 			if (connector != null) {
 				return TasksUiPlugin.getDefault().getBrandingIcon(connector.getConnectorKind());
 			}
-		} else if (element instanceof AbstractTask) {
-			AbstractTask repositoryTask = (AbstractTask) element;
+		} else if (element instanceof ITask) {
+			ITask repositoryTask = (ITask) element;
 			AbstractRepositoryConnector connector = TasksUi.getRepositoryManager().getRepositoryConnector(
 					repositoryTask.getConnectorKind());
 			if (connector != null) {
@@ -457,8 +459,8 @@ public class TaskListToolTip extends ToolTip {
 		String incommingText = getIncommingText(currentTipElement);
 		if (incommingText != null) {
 			Image image = CommonImages.getImage(CommonImages.OVERLAY_SYNC_INCOMMING);
-			if (currentTipElement instanceof AbstractTask) {
-				AbstractTask task = (AbstractTask) currentTipElement;
+			if (currentTipElement instanceof ITask) {
+				ITask task = (ITask) currentTipElement;
 				if (task.getLastReadTimeStamp() == null) {
 					image = CommonImages.getImage(CommonImages.OVERLAY_SYNC_INCOMMING_NEW);
 				}
@@ -514,7 +516,7 @@ public class TaskListToolTip extends ToolTip {
 		return composite;
 	}
 
-	private String getHelpText(AbstractTaskContainer element) {
+	private String getHelpText(ITaskElement element) {
 		if (element instanceof TaskCategory || element instanceof AbstractRepositoryQuery) {
 			if (AbstractTaskListFilter.hasDescendantIncoming(element)) {
 				TaskListView taskListView = TaskListView.getFromActivePerspective();
@@ -526,8 +528,8 @@ public class TaskListToolTip extends ToolTip {
 						Object[] children = ((TaskListContentProvider) taskListView.getViewer().getContentProvider()).getChildren(element);
 						boolean hasIncoming = false;
 						for (Object child : children) {
-							if (child instanceof AbstractTask) {
-								if (((AbstractTask) child).getSynchronizationState().isIncoming()) {
+							if (child instanceof ITask) {
+								if (((ITask) child).getSynchronizationState().isIncoming()) {
 									hasIncoming = true;
 									break;
 								}
@@ -560,7 +562,7 @@ public class TaskListToolTip extends ToolTip {
 		return composite;
 	}
 
-	private String getSynchText(AbstractTaskContainer element) {
+	private String getSynchText(ITaskElement element) {
 		if (element instanceof AbstractRepositoryQuery) {
 			String syncStamp = ((AbstractRepositoryQuery) element).getLastSynchronizedTimeStamp();
 			if (syncStamp != null) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListView.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListView.java
index 00d77e8f6..a969cc223 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListView.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskListView.java
@@ -53,9 +53,14 @@ import org.eclipse.jface.window.Window;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonThemes;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.UncategorizedTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.UnmatchedTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.ui.AbstractTaskListFilter;
 import org.eclipse.mylyn.internal.tasks.ui.CategorizedPresentation;
 import org.eclipse.mylyn.internal.tasks.ui.IDynamicSubMenuContributor;
@@ -94,15 +99,12 @@ import org.eclipse.mylyn.internal.tasks.ui.editors.TaskListChangeAdapter;
 import org.eclipse.mylyn.internal.tasks.ui.util.TaskDragSourceListener;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskListTableSorter.SortByIndex;
 import org.eclipse.mylyn.internal.tasks.ui.workingsets.TaskWorkingSetUpdater;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskActivityListener;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskListChangeListener;
 import org.eclipse.mylyn.tasks.core.TaskActivityAdapter;
 import org.eclipse.mylyn.tasks.core.TaskContainerDelta;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditorInput;
 import org.eclipse.swt.SWT;
@@ -328,8 +330,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 
 	private final Listener CATEGORY_GRADIENT_DRAWER = new Listener() {
 		public void handleEvent(Event event) {
-			if (event.item.getData() instanceof AbstractTaskContainer
-					&& !(event.item.getData() instanceof AbstractTask)) {
+			if (event.item.getData() instanceof ITaskElement && !(event.item.getData() instanceof ITask)) {
 				Scrollable scrollable = (Scrollable) event.widget;
 				GC gc = event.gc;
 
@@ -402,7 +403,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		}
 
 		@Override
-		public void taskActivated(final AbstractTask task) {
+		public void taskActivated(final ITask task) {
 			if (task != null) {
 				PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {
 					public void run() {
@@ -416,7 +417,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		}
 
 		@Override
-		public void taskDeactivated(final AbstractTask task) {
+		public void taskDeactivated(final ITask task) {
 			PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {
 				public void run() {
 					refreshJob.refreshTask(task);
@@ -598,7 +599,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 	}
 
 	private void updateDescription() {
-		AbstractTask task = TasksUi.getTaskActivityManager().getActiveTask();
+		ITask task = TasksUi.getTaskActivityManager().getActiveTask();
 		if (getSite() == null || getSite().getPage() == null) {
 			return;
 		}
@@ -781,7 +782,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 				Object selectedNode = ((Tree) e.widget).getItem(new Point(e.x + 70, e.y));
 				if (selectedNode instanceof TreeItem) {
 					Object selectedObject = ((TreeItem) selectedNode).getData();
-					if (selectedObject instanceof AbstractTask) {
+					if (selectedObject instanceof ITask) {
 						if (e.x > activationImageOffset && e.x < activationImageOffset + 13) {
 							taskListCellModifier.toggleTaskActivation((TreeItem) selectedNode);
 						}
@@ -851,9 +852,9 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		getViewer().addSelectionChangedListener(new ISelectionChangedListener() {
 			public void selectionChanged(SelectionChangedEvent event) {
 				Object selectedObject = ((IStructuredSelection) getViewer().getSelection()).getFirstElement();
-				if (selectedObject instanceof AbstractTaskContainer) {
-					updateActionEnablement(renameAction, (AbstractTaskContainer) selectedObject);
-					updateActionEnablement(deleteAction, (AbstractTaskContainer) selectedObject);
+				if (selectedObject instanceof ITaskElement) {
+					updateActionEnablement(renameAction, (ITaskElement) selectedObject);
+					updateActionEnablement(deleteAction, (ITaskElement) selectedObject);
 				}
 			}
 		});
@@ -1035,7 +1036,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		final IWorkbench workbench = PlatformUI.getWorkbench();
 		workbench.getDisplay().asyncExec(new Runnable() {
 			public void run() {
-				AbstractTask task = TasksUi.getTaskActivityManager().getActiveTask();
+				ITask task = TasksUi.getTaskActivityManager().getActiveTask();
 				if (task != null) {
 					getViewer().expandToLevel(task, 0);
 				}
@@ -1105,24 +1106,24 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 	 */
 	private void fillContextMenu(final IMenuManager manager) {
 		updateDrillDownActions();
-		final AbstractTaskContainer element;
+		final ITaskElement element;
 
 		final Object firstSelectedObject = ((IStructuredSelection) getViewer().getSelection()).getFirstElement();
-		if (firstSelectedObject instanceof AbstractTaskContainer) {
-			element = (AbstractTaskContainer) firstSelectedObject;
+		if (firstSelectedObject instanceof ITaskElement) {
+			element = (ITaskElement) firstSelectedObject;
 		} else {
 			element = null;
 		}
-		final List<AbstractTaskContainer> selectedElements = getSelectedTaskContainers();
+		final List<ITaskElement> selectedElements = getSelectedTaskContainers();
 		AbstractTask task = null;
-		if (element instanceof AbstractTask) {
+		if (element instanceof ITask) {
 			task = (AbstractTask) element;
 		}
 
 		manager.add(new Separator(ID_SEPARATOR_NEW));
 		manager.add(new Separator());
 
-		if (element instanceof AbstractTask) {
+		if (element instanceof ITask) {
 			addAction(openAction, manager, element);
 		}
 		addAction(openWithBrowser, manager, element);
@@ -1168,11 +1169,11 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		}
 		// This should also test for null, or else nothing to delete!
 		addAction(deleteAction, manager, element);
-		if (!(element instanceof AbstractTask)) {
+		if (!(element instanceof ITask)) {
 			addAction(renameAction, manager, element);
 		}
 
-		if (element != null && !(element instanceof AbstractTask)) {
+		if (element != null && !(element instanceof ITask)) {
 			manager.add(goIntoAction);
 		}
 		if (drilledIntoCategory != null) {
@@ -1181,7 +1182,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		manager.add(new Separator(ID_SEPARATOR_CONTEXT));
 		manager.add(new Separator(ID_SEPARATOR_OPERATIONS));
 
-		if (element instanceof AbstractTask) {
+		if (element instanceof ITask) {
 			for (String menuPath : dynamicMenuMap.keySet()) {
 				if (ID_SEPARATOR_CONTEXT.equals(menuPath)) {
 					for (IDynamicSubMenuContributor contributor : dynamicMenuMap.get(menuPath)) {
@@ -1214,24 +1215,24 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		manager.add(new Separator(ID_SEPARATOR_PROPERTIES));
 	}
 
-	public List<AbstractTaskContainer> getSelectedTaskContainers() {
-		List<AbstractTaskContainer> selectedElements = new ArrayList<AbstractTaskContainer>();
+	public List<ITaskElement> getSelectedTaskContainers() {
+		List<ITaskElement> selectedElements = new ArrayList<ITaskElement>();
 		for (Iterator<?> i = ((IStructuredSelection) getViewer().getSelection()).iterator(); i.hasNext();) {
 			Object object = i.next();
-			if (object instanceof AbstractTaskContainer) {
-				selectedElements.add((AbstractTaskContainer) object);
+			if (object instanceof ITaskElement) {
+				selectedElements.add((ITaskElement) object);
 			}
 		}
 		return selectedElements;
 	}
 
-	private void addMenuManager(IMenuManager menuToAdd, IMenuManager manager, AbstractTaskContainer element) {
-		if ((element instanceof AbstractTask) || element instanceof AbstractRepositoryQuery) {
+	private void addMenuManager(IMenuManager menuToAdd, IMenuManager manager, ITaskElement element) {
+		if ((element instanceof ITask) || element instanceof AbstractRepositoryQuery) {
 			manager.add(menuToAdd);
 		}
 	}
 
-	private void addAction(Action action, IMenuManager manager, AbstractTaskContainer element) {
+	private void addAction(Action action, IMenuManager manager, ITaskElement element) {
 		manager.add(action);
 		if (element != null) {
 			updateActionEnablement(action, element);
@@ -1239,10 +1240,10 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 	}
 
 	// FIXME move the enablement to the action classes
-	private void updateActionEnablement(Action action, AbstractTaskContainer element) {
-		if (element instanceof AbstractTask) {
+	private void updateActionEnablement(Action action, ITaskElement element) {
+		if (element instanceof ITask) {
 			if (action instanceof OpenWithBrowserAction) {
-				if (((AbstractTask) element).hasValidUrl()) {
+				if (((ITask) element).hasValidUrl()) {
 					action.setEnabled(true);
 				} else {
 					action.setEnabled(false);
@@ -1441,7 +1442,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		if (selection instanceof StructuredSelection) {
 			StructuredSelection structuredSelection = (StructuredSelection) selection;
 			Object element = structuredSelection.getFirstElement();
-			if (element instanceof AbstractTaskContainer) {
+			if (element instanceof ITaskElement) {
 				drilledIntoCategory = (AbstractTaskContainer) element;
 				drillDownAdapter.goInto();
 				IActionBars bars = getViewSite().getActionBars();
@@ -1470,7 +1471,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		if (selection instanceof StructuredSelection) {
 			StructuredSelection structuredSelection = (StructuredSelection) selection;
 			Object element = structuredSelection.getFirstElement();
-			if (element instanceof AbstractTask) {
+			if (element instanceof ITask) {
 				return (AbstractTask) structuredSelection.getFirstElement();
 			}
 		}
@@ -1484,7 +1485,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 				return null;
 			}
 			Object element = structuredSelection.getFirstElement();
-			if (element instanceof AbstractTask) {
+			if (element instanceof ITask) {
 				return (AbstractTask) structuredSelection.getFirstElement();
 			}
 		}
@@ -1512,7 +1513,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		return filteredTree;
 	}
 
-	public void selectedAndFocusTask(AbstractTask task) {
+	public void selectedAndFocusTask(ITask task) {
 		if (task == null || getViewer().getControl().isDisposed()) {
 			return;
 		}
@@ -1525,10 +1526,10 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 	private void saveSelection() {
 		IStructuredSelection selection = (IStructuredSelection) getViewer().getSelection();
 		if (!selection.isEmpty()) {
-			if (selection.getFirstElement() instanceof AbstractTaskContainer) {
+			if (selection.getFirstElement() instanceof ITaskElement) {
 				// make sure the new selection is inserted at the end of the
 				// list
-				String handle = ((AbstractTaskContainer) selection.getFirstElement()).getHandleIdentifier();
+				String handle = ((ITaskElement) selection.getFirstElement()).getHandleIdentifier();
 				lastSelectionByTaskHandle.remove(handle);
 				lastSelectionByTaskHandle.put(handle, selection);
 
@@ -1541,7 +1542,7 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 		}
 	}
 
-	private IStructuredSelection restoreSelection(AbstractTaskContainer task) {
+	private IStructuredSelection restoreSelection(ITaskElement task) {
 		IStructuredSelection selection = lastSelectionByTaskHandle.get(task.getHandleIdentifier());
 		if (selection != null) {
 			return selection;
@@ -1643,8 +1644,8 @@ public class TaskListView extends ViewPart implements IPropertyChangeListener {
 	private void jumpToEditorTask(IEditorPart editor) {
 		IEditorInput input = editor.getEditorInput();
 		if (input instanceof TaskEditorInput) {
-			AbstractTask task = ((TaskEditorInput) input).getTask();
-			AbstractTask selected = getSelectedTask();
+			ITask task = ((TaskEditorInput) input).getTask();
+			ITask selected = getSelectedTask();
 			if (selected == null || !selected.equals(task)) {
 				selectedAndFocusTask(task);
 			}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskScheduleContentProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskScheduleContentProvider.java
index 0a9b6d2ca..39ebae8b9 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskScheduleContentProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskScheduleContentProvider.java
@@ -12,12 +12,13 @@ import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskDelegate;
 import org.eclipse.mylyn.internal.tasks.core.TaskActivityManager;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 
 /**
  * Used by Scheduled task list presentation
@@ -66,18 +67,18 @@ public class TaskScheduleContentProvider extends TaskListContentProvider {
 
 	@Override
 	public Object[] getChildren(Object parent) {
-		Set<AbstractTask> result = new HashSet<AbstractTask>();
-		if (parent instanceof AbstractTask) {
+		Set<ITask> result = new HashSet<ITask>();
+		if (parent instanceof ITask) {
 			// flat presentation (no subtasks revealed in Scheduled mode)
 		} else if (parent instanceof ScheduledTaskContainer) {
-			for (AbstractTask child : ((ScheduledTaskContainer) parent).getChildren()) {
+			for (ITask child : ((ScheduledTaskContainer) parent).getChildren()) {
 				if (!filter(parent, child)) {
 					result.add(child);
 				}
 			}
 
-		} else if (parent instanceof AbstractTaskContainer) {
-			for (AbstractTask child : ((AbstractTaskContainer) parent).getChildren()) {
+		} else if (parent instanceof ITaskElement) {
+			for (ITask child : ((ITaskElement) parent).getChildren()) {
 				result.add(child);
 			}
 		}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskTableLabelProvider.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskTableLabelProvider.java
index dc9899589..5fd5af54c 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskTableLabelProvider.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/views/TaskTableLabelProvider.java
@@ -16,10 +16,10 @@ import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ITableColorProvider;
 import org.eclipse.jface.viewers.ITableFontProvider;
 import org.eclipse.jface.viewers.ITableLabelProvider;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.ScheduledTaskContainer;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Font;
 import org.eclipse.swt.graphics.Image;
@@ -42,7 +42,7 @@ public class TaskTableLabelProvider extends DecoratingLabelProvider implements I
 	}
 
 	public String getColumnText(Object obj, int columnIndex) {
-		if (obj instanceof AbstractTaskContainer) {
+		if (obj instanceof ITaskElement) {
 			switch (columnIndex) {
 			case 0:
 				if (obj instanceof ScheduledTaskContainer) {
@@ -59,7 +59,7 @@ public class TaskTableLabelProvider extends DecoratingLabelProvider implements I
 	}
 
 	public Image getColumnImage(Object element, int columnIndex) {
-		if (!(element instanceof AbstractTaskContainer)) {
+		if (!(element instanceof ITaskElement)) {
 			return null;
 		}
 		if (columnIndex == 0) {
@@ -77,7 +77,7 @@ public class TaskTableLabelProvider extends DecoratingLabelProvider implements I
 	}
 
 	public Color getBackground(Object element, int columnIndex) {
-		if (element instanceof AbstractTaskContainer && !(element instanceof AbstractTask)) {
+		if (element instanceof ITaskElement && !(element instanceof ITask)) {
 			return categoryBackgroundColor;
 		} else if (element instanceof AbstractRepositoryQuery) {
 			return categoryBackgroundColor;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/NewAttachmentWizard.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/NewAttachmentWizard.java
index bcfec27df..9496f5ee3 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/NewAttachmentWizard.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/NewAttachmentWizard.java
@@ -30,8 +30,10 @@ import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
 import org.eclipse.mylyn.internal.provisional.commons.ui.ScreenshotCreationPage;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.LocalAttachment;
 import org.eclipse.mylyn.internal.tasks.core.RepositoryTaskHandleUtil;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractAttachmentHandler;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.ui.AttachmentUtil;
@@ -40,10 +42,9 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.AbstractRepositoryTaskEditorInput;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.mylyn.tasks.ui.TasksUiUtil;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
@@ -251,7 +252,7 @@ public class NewAttachmentWizard extends Wizard {
 	/**
 	 * If task is open, force inplace refresh Must be called from UI thread.
 	 */
-	public static boolean forceRefreshInplace(AbstractTask task) {
+	public static boolean forceRefreshInplace(ITask task) {
 		if (task != null) {
 			String handleTarget = task.getHandleIdentifier();
 			for (TaskEditor editor : TasksUiInternal.getActiveRepositoryTaskEditors()) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskAttachmentWizard.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskAttachmentWizard.java
index d1e6de01b..7e58cc1d2 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskAttachmentWizard.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskAttachmentWizard.java
@@ -36,7 +36,7 @@ import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.core.data.AbstractTaskAttachmentSource;
 import org.eclipse.mylyn.tasks.core.data.TaskAttachmentModel;
@@ -230,7 +230,7 @@ public class TaskAttachmentWizard extends Wizard {
 
 	private PreviewAttachmentPage2 previewPage;
 
-	public TaskAttachmentWizard(TaskRepository taskRepository, AbstractTask task, TaskAttribute taskAttachment) {
+	public TaskAttachmentWizard(TaskRepository taskRepository, ITask task, TaskAttribute taskAttachment) {
 		Assert.isNotNull(taskRepository);
 		Assert.isNotNull(taskAttachment);
 		this.model = new TaskAttachmentModel(taskRepository, task, taskAttachment);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskDataExportWizard.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskDataExportWizard.java
index 1417583b1..90ed8f602 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskDataExportWizard.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/wizards/TaskDataExportWizard.java
@@ -23,10 +23,11 @@ import org.eclipse.jface.wizard.Wizard;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.context.core.ContextCore;
 import org.eclipse.mylyn.context.core.IInteractionContextManager;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.ITasksCoreConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.util.TaskDataExportOperation;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IExportWizard;
 import org.eclipse.ui.IWorkbench;
@@ -152,7 +153,7 @@ public class TaskDataExportWizard extends Wizard implements IExportWizard {
 				}
 
 				if (exportPage.exportTaskContexts()) {
-					for (AbstractTask task : taskContextsToExport) {
+					for (ITask task : taskContextsToExport) {
 						File contextFile = ContextCore.getContextManager().getFileForContext(
 								task.getHandleIdentifier());
 						File destTaskFile = new File(destDir + File.separator + contextFile.getName());
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetAdapterFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetAdapterFactory.java
index 829a40b70..0ed9a4852 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetAdapterFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetAdapterFactory.java
@@ -10,7 +10,7 @@ package org.eclipse.mylyn.internal.tasks.ui.workingsets;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.IAdapterFactory;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.ui.IMemento;
 import org.eclipse.ui.IPersistableElement;
 
@@ -32,10 +32,10 @@ public class TaskWorkingSetAdapterFactory implements IAdapterFactory {
 	}
 
 	public Object getAdapter(final Object adaptableObject, @SuppressWarnings("unchecked") Class adapterType) {
-		if (adapterType == IPersistableElement.class && adaptableObject instanceof AbstractTaskContainer) {
+		if (adapterType == IPersistableElement.class && adaptableObject instanceof ITaskElement) {
 			return new IPersistableElement() {
 				public void saveState(IMemento memento) {
-					AbstractTaskContainer container = (AbstractTaskContainer) adaptableObject;
+					ITaskElement container = (ITaskElement) adaptableObject;
 					memento.putString(TaskWorkingSetElementFactory.HANDLE_TASK, container.getHandleIdentifier());
 				}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementAdapter.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementAdapter.java
index 17961c65e..236d88c62 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementAdapter.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementAdapter.java
@@ -13,7 +13,7 @@ import java.util.List;
 
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.IAdaptable;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.ui.IWorkingSet;
 import org.eclipse.ui.IWorkingSetElementAdapter;
 
@@ -25,7 +25,7 @@ public class TaskWorkingSetElementAdapter implements IWorkingSetElementAdapter {
 
 	public IAdaptable[] adaptElements(IWorkingSet workingSet, IAdaptable[] elements) {
 		for (IAdaptable adaptable : elements) {
-			if (!(adaptable instanceof AbstractTaskContainer)) {
+			if (!(adaptable instanceof ITaskElement)) {
 				return selectContainers(elements);
 			}
 		}
@@ -35,7 +35,7 @@ public class TaskWorkingSetElementAdapter implements IWorkingSetElementAdapter {
 	private IAdaptable[] selectContainers(IAdaptable[] elements) {
 		List<IAdaptable> containers = new ArrayList<IAdaptable>(elements.length);
 		for (IAdaptable adaptable : elements) {
-			if (adaptable instanceof AbstractTaskContainer) {
+			if (adaptable instanceof ITaskElement) {
 				containers.add(adaptable);
 			} else if (adaptable instanceof IProject) {
 				containers.add(adaptable);
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementFactory.java
index e9968f3b5..7b25fc3df 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetElementFactory.java
@@ -14,9 +14,9 @@ import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.TaskList;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
 import org.eclipse.ui.IElementFactory;
 import org.eclipse.ui.IMemento;
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetPage.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetPage.java
index e2018c37f..e12159eee 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetPage.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetPage.java
@@ -31,12 +31,13 @@ import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerSorter;
 import org.eclipse.jface.wizard.WizardPage;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskElementLabelProvider;
 import org.eclipse.mylyn.internal.tasks.ui.views.TaskRepositoryLabelProvider;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.swt.SWT;
@@ -224,7 +225,7 @@ public class TaskWorkingSetPage extends WizardPage implements IWorkingSetPage {
 		private final WorkbenchLabelProvider workbenchLabelProvider = new WorkbenchLabelProvider();
 
 		public Image getImage(Object element) {
-			if (element instanceof AbstractTaskContainer) {
+			if (element instanceof ITaskElement) {
 				return taskLabelProvider.getImage(element);
 			} else if (element instanceof TaskRepository) {
 				return taskRepositoryLabelProvider.getImage(element);
@@ -236,7 +237,7 @@ public class TaskWorkingSetPage extends WizardPage implements IWorkingSetPage {
 		}
 
 		public String getText(Object element) {
-			if (element instanceof AbstractTaskContainer) {
+			if (element instanceof ITaskElement) {
 				return taskLabelProvider.getText(element);
 			} else if (element instanceof TaskRepository) {
 				return taskRepositoryLabelProvider.getText(element);
@@ -290,7 +291,7 @@ public class TaskWorkingSetPage extends WizardPage implements IWorkingSetPage {
 		Object[] elements = treeViewer.getCheckedElements();
 		Set<IAdaptable> validElements = new HashSet<IAdaptable>();
 		for (Object element : elements) {
-			if (element instanceof AbstractTaskContainer || element instanceof IProject) {
+			if (element instanceof ITaskElement || element instanceof IProject) {
 				validElements.add((IAdaptable) element);
 			}
 		}
@@ -499,7 +500,7 @@ public class TaskWorkingSetPage extends WizardPage implements IWorkingSetPage {
 		BusyIndicator.showWhile(getShell().getDisplay(), new Runnable() {
 			public void run() {
 				IAdaptable element = (IAdaptable) event.getElement();
-				if (element instanceof AbstractTaskContainer || element instanceof IProject) {
+				if (element instanceof ITaskElement || element instanceof IProject) {
 					treeViewer.setGrayed(element, false);
 				} else if (element instanceof ElementCategory) {
 					for (Object child : ((ElementCategory) element).getChildren(null)) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetUpdater.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetUpdater.java
index e92ca473e..3a130847e 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetUpdater.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/internal/tasks/ui/workingsets/TaskWorkingSetUpdater.java
@@ -21,10 +21,10 @@ import org.eclipse.core.resources.IResourceChangeListener;
 import org.eclipse.core.resources.IResourceDelta;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.IAdaptable;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.core.TaskCategory;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskListChangeListener;
 import org.eclipse.mylyn.tasks.core.TaskContainerDelta;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
@@ -97,9 +97,9 @@ public class TaskWorkingSetUpdater implements IWorkingSetUpdater, ITaskListChang
 	private void checkElementExistence(IWorkingSet workingSet) {
 		ArrayList<IAdaptable> list = new ArrayList<IAdaptable>();
 		for (IAdaptable adaptable : workingSet.getElements()) {
-			if (adaptable instanceof AbstractTaskContainer) {
-				String handle = ((AbstractTaskContainer) adaptable).getHandleIdentifier();
-				for (AbstractTaskContainer element : TasksUiPlugin.getTaskListManager().getTaskList().getRootElements()) {
+			if (adaptable instanceof ITaskElement) {
+				String handle = ((ITaskElement) adaptable).getHandleIdentifier();
+				for (ITaskElement element : TasksUiPlugin.getTaskListManager().getTaskList().getRootElements()) {
 					if (element != null && element.getHandleIdentifier().equals(handle)) {
 						list.add(adaptable);
 					}
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/AbstractRepositoryConnectorUi.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/AbstractRepositoryConnectorUi.java
index b208f0f83..a80946974 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/AbstractRepositoryConnectorUi.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/AbstractRepositoryConnectorUi.java
@@ -22,19 +22,20 @@ import org.eclipse.jface.wizard.IWizardPage;
 import org.eclipse.jface.wizard.WizardDialog;
 import org.eclipse.jface.wizard.WizardPage;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskSelection;
 import org.eclipse.mylyn.internal.tasks.ui.OpenRepositoryTaskJob;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.CommonAddExistingTaskWizard;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.ITaskComment;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskRepositoryManager;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.PriorityLevel;
 import org.eclipse.mylyn.tasks.core.data.TaskAttachmentModel;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
 import org.eclipse.mylyn.tasks.ui.wizards.AbstractRepositorySettingsPage;
@@ -71,6 +72,7 @@ public abstract class AbstractRepositoryConnectorUi {
 	 * @param repository
 	 * @param queryToEdit
 	 * 		can be null
+	 * @since 3.0
 	 */
 	public abstract IWizard getQueryWizard(TaskRepository repository, AbstractRepositoryQuery queryToEdit);
 
@@ -91,8 +93,10 @@ public abstract class AbstractRepositoryConnectorUi {
 	 * Override to return a custom task editor ID. If overriding this method the connector becomes responsible for
 	 * showing the additional pages handled by the default task editor. As of Mylyn 2.0M2 these are the Planning and
 	 * Context pages.
+	 * 
+	 * @since 3.0
 	 */
-	public String getTaskEditorId(AbstractTask repositoryTask) {
+	public String getTaskEditorId(ITask repositoryTask) {
 		return TaskEditor.ID_EDITOR;
 	}
 
@@ -108,8 +112,9 @@ public abstract class AbstractRepositoryConnectorUi {
 	/**
 	 * @param repositoryTask
 	 * 		can be null
+	 * @since 3.0
 	 */
-	public String getTaskKindLabel(AbstractTask task) {
+	public String getTaskKindLabel(ITask task) {
 		return LABEL_TASK_DEFAULT;
 	}
 
@@ -118,11 +123,13 @@ public abstract class AbstractRepositoryConnectorUi {
 	 * 
 	 * For connectors that have a decorator that they want to reuse, the connector can maintain a reference to the label
 	 * provider and get the descriptor from the images it returns.
+	 * 
+	 * @since 3.0
 	 */
-	public ImageDescriptor getTaskListElementIcon(AbstractTaskContainer element) {
+	public ImageDescriptor getTaskListElementIcon(ITaskElement element) {
 		if (element instanceof AbstractRepositoryQuery) {
 			return TasksUiImages.QUERY;
-		} else if (element instanceof AbstractTask) {
+		} else if (element instanceof ITask) {
 			return TasksUiImages.TASK;
 		} else {
 			return null;
@@ -131,19 +138,26 @@ public abstract class AbstractRepositoryConnectorUi {
 
 	/**
 	 * Task kind overlay, recommended to override with connector-specific overlay.
+	 * 
+	 * @since 3.0
 	 */
-	public ImageDescriptor getTaskKindOverlay(AbstractTask task) {
+	public ImageDescriptor getTaskKindOverlay(ITask task) {
 		return null;
 	}
 
 	/**
 	 * Connector-specific priority icons. Not recommended to override since priority icons are used elsewhere in the
 	 * Task List UI (e.g. filter selection in view menu).
+	 * 
+	 * @since 3.0
 	 */
-	public ImageDescriptor getTaskPriorityOverlay(AbstractTask task) {
+	public ImageDescriptor getTaskPriorityOverlay(ITask task) {
 		return TasksUiImages.getImageDescriptorForPriority(PriorityLevel.fromString(task.getPriority()));
 	}
 
+	/**
+	 * @since 3.0
+	 */
 	public void openEditQueryDialog(AbstractRepositoryQuery query) {
 		try {
 			TaskRepository repository = TasksUi.getRepositoryManager().getRepository(query.getConnectorKind(),
@@ -205,7 +219,7 @@ public abstract class AbstractRepositoryConnectorUi {
 	 * @return a url of a page for the history of the task; null, if no history url is available
 	 * @since 3.0
 	 */
-	public String getTaskHistoryUrl(TaskRepository taskRepository, AbstractTask task) {
+	public String getTaskHistoryUrl(TaskRepository taskRepository, ITask task) {
 		return null;
 	}
 
@@ -216,8 +230,7 @@ public abstract class AbstractRepositoryConnectorUi {
 	 * @return a reference to <code>comment</code>; null, if no reference is available
 	 * @since 3.0
 	 */
-	public String getReply(TaskRepository taskRepository, AbstractTask task, ITaskComment taskComment,
-			boolean includeTask) {
+	public String getReply(TaskRepository taskRepository, ITask task, ITaskComment taskComment, boolean includeTask) {
 		return null;
 	}
 
@@ -266,7 +279,10 @@ public abstract class AbstractRepositoryConnectorUi {
 		return customNotificationHandling;
 	}
 
-	public boolean supportsDueDates(AbstractTask task) {
+	/**
+	 * @since 3.0
+	 */
+	public boolean supportsDueDates(ITask task) {
 		return false;
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/TasksUiUtil.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/TasksUiUtil.java
index b0e9b3f71..d2d6cf25d 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/TasksUiUtil.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/TasksUiUtil.java
@@ -38,8 +38,12 @@ import org.eclipse.jface.wizard.IWizard;
 import org.eclipse.jface.wizard.WizardDialog;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.commons.net.Policy;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
 import org.eclipse.mylyn.internal.tasks.core.LocalTask;
 import org.eclipse.mylyn.internal.tasks.core.TaskDataStorageManager;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.RepositoryTaskData;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskSelection;
@@ -52,12 +56,10 @@ import org.eclipse.mylyn.internal.tasks.ui.wizards.EditRepositoryWizard;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.MultiRepositoryAwareWizard;
 import org.eclipse.mylyn.internal.tasks.ui.wizards.NewLocalTaskWizard;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskList;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditor;
 import org.eclipse.mylyn.tasks.ui.editors.TaskEditorInput;
 import org.eclipse.swt.custom.BusyIndicator;
@@ -94,7 +96,10 @@ public class TasksUiUtil {
 
 	public static final String PREFS_PAGE_ID_COLORS_AND_FONTS = "org.eclipse.ui.preferencePages.ColorsAndFonts";
 
-	public static void closeEditorInActivePage(AbstractTask task, boolean save) {
+	/**
+	 * @since 3.0
+	 */
+	public static void closeEditorInActivePage(ITask task, boolean save) {
 		IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
 		if (window == null) {
 			return;
@@ -240,8 +245,8 @@ public class TasksUiUtil {
 		} else if (element instanceof AbstractRepositoryQuery) {
 			AbstractRepositoryQuery query = (AbstractRepositoryQuery) element;
 			return TasksUi.getRepositoryManager().getRepository(query.getConnectorKind(), query.getRepositoryUrl());
-		} else if (element instanceof AbstractTask) {
-			AbstractTask task = (AbstractTask) element;
+		} else if (element instanceof ITask) {
+			ITask task = (ITask) element;
 			return TasksUi.getRepositoryManager().getRepository(task.getConnectorKind(), task.getRepositoryUrl());
 		} else if (element instanceof IResource) {
 			IResource resource = (IResource) element;
@@ -252,9 +257,9 @@ public class TasksUiUtil {
 			if (resource != null) {
 				return TasksUiPlugin.getDefault().getRepositoryForResource(resource);
 			} else {
-				AbstractTask task = (AbstractTask) adaptable.getAdapter(AbstractTask.class);
+				ITask task = (ITask) adaptable.getAdapter(AbstractTask.class);
 				if (task != null) {
-					AbstractTask rtask = task;
+					ITask rtask = task;
 					return TasksUi.getRepositoryManager().getRepository(rtask.getConnectorKind(),
 							rtask.getRepositoryUrl());
 				}
@@ -266,10 +271,10 @@ public class TasksUiUtil {
 		return null;
 	}
 
-	private static String getTaskEditorId(final AbstractTask task) {
+	private static String getTaskEditorId(final ITask task) {
 		String taskEditorId = TaskEditor.ID_EDITOR;
 		if (task != null) {
-			AbstractTask repositoryTask = task;
+			ITask repositoryTask = task;
 			AbstractRepositoryConnectorUi repositoryUi = TasksUiPlugin.getConnectorUi(repositoryTask.getConnectorKind());
 			String customTaskEditorId = repositoryUi.getTaskEditorId(repositoryTask);
 			if (customTaskEditorId != null) {
@@ -281,6 +286,7 @@ public class TasksUiUtil {
 
 	/**
 	 * @deprecated use {@link #openTaskAndRefresh(AbstractTask)} instead
+	 * @since 3.0
 	 */
 	@Deprecated
 	public static void openEditor(final AbstractTask task, boolean newTask) {
@@ -291,6 +297,7 @@ public class TasksUiUtil {
 	 * Set asyncExec false for testing purposes.
 	 * 
 	 * @deprecated use {@link #openTaskAndRefresh(AbstractTask)} instead
+	 * @since 3.0
 	 */
 	@Deprecated
 	public static void openEditor(final AbstractTask task, boolean asyncExec, final boolean newTask) {
@@ -372,6 +379,7 @@ public class TasksUiUtil {
 
 	/**
 	 * @deprecated use {@link #openTask(AbstractTask)} instead
+	 * @since 3.0
 	 */
 	@Deprecated
 	public static void openEditor(AbstractTask task, String pageId) {
@@ -480,7 +488,7 @@ public class TasksUiUtil {
 	/**
 	 * @since 3.0
 	 */
-	public static boolean openTaskInBackground(AbstractTask task, boolean bringToTop) {
+	public static boolean openTaskInBackground(ITask task, boolean bringToTop) {
 		IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
 		if (window != null) {
 			IEditorPart activeEditor = null;
@@ -510,7 +518,7 @@ public class TasksUiUtil {
 	/**
 	 * @since 3.0
 	 */
-	public static boolean openTask(AbstractTask task) {
+	public static boolean openTask(ITask task) {
 		Assert.isNotNull(task);
 
 		IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
@@ -661,7 +669,7 @@ public class TasksUiUtil {
 	/**
 	 * @since 3.0
 	 */
-	public static boolean openTaskAndRefresh(final AbstractTask task) {
+	public static boolean openTaskAndRefresh(final ITask task) {
 		if (openTask(task)) {
 			Job updateTaskData = new Job("Refresh Task") {
 				@Override
@@ -747,16 +755,17 @@ public class TasksUiUtil {
 
 	/**
 	 * @deprecated Use {@link TasksUiInternal#refreshAndOpenTaskListElement(AbstractTaskContainer)} instead
+	 * @since 3.0
 	 */
 	@Deprecated
-	public static void refreshAndOpenTaskListElement(AbstractTaskContainer element) {
+	public static void refreshAndOpenTaskListElement(ITaskElement element) {
 		TasksUiInternal.refreshAndOpenTaskListElement(element);
 	}
 
 	/**
 	 * If task is already open and has incoming, must force refresh in place
 	 */
-	private static boolean refreshIfOpen(AbstractTask task, IEditorInput editorInput) {
+	private static boolean refreshIfOpen(ITask task, IEditorInput editorInput) {
 		if (task != null) {
 			if (task.getSynchronizationState() == SynchronizationState.INCOMING
 					|| task.getSynchronizationState() == SynchronizationState.CONFLICT) {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorFactory.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorFactory.java
index a2f1a923f..d0fb0d1b5 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorFactory.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorFactory.java
@@ -8,7 +8,7 @@
 
 package org.eclipse.mylyn.tasks.ui.editors;
 
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.ui.IEditorInput;
 import org.eclipse.ui.IEditorPart;
 
@@ -24,11 +24,17 @@ public abstract class AbstractTaskEditorFactory {
 
 	public abstract IEditorPart createEditor(TaskEditor parentEditor, IEditorInput editorInput);
 
-	public abstract IEditorInput createEditorInput(AbstractTask task);
+	/**
+	 * @since 3.0
+	 */
+	public abstract IEditorInput createEditorInput(ITask task);
 
 	public abstract String getTitle();
 
-	public abstract boolean canCreateEditorFor(AbstractTask task);
+	/**
+	 * @since 3.0
+	 */
+	public abstract boolean canCreateEditorFor(ITask task);
 
 	public abstract boolean canCreateEditorFor(IEditorInput input);
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorPage.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorPage.java
index 2ad0258a5..2cdf2d21d 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorPage.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/AbstractTaskEditorPage.java
@@ -36,6 +36,8 @@ import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.jface.window.Window;
 import org.eclipse.mylyn.commons.core.StatusHandler;
 import org.eclipse.mylyn.internal.provisional.commons.ui.CommonImages;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.internal.tasks.ui.AttachmentUtil;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
@@ -55,13 +57,12 @@ import org.eclipse.mylyn.internal.tasks.ui.editors.TaskEditorSummaryPart;
 import org.eclipse.mylyn.internal.tasks.ui.editors.TaskListChangeAdapter;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
-import org.eclipse.mylyn.tasks.core.AbstractTaskContainer;
+import org.eclipse.mylyn.tasks.core.ITask;
+import org.eclipse.mylyn.tasks.core.ITaskElement;
 import org.eclipse.mylyn.tasks.core.ITaskListChangeListener;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskContainerDelta;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
-import org.eclipse.mylyn.tasks.core.AbstractTask.SynchronizationState;
 import org.eclipse.mylyn.tasks.core.data.ITaskDataWorkingCopy;
 import org.eclipse.mylyn.tasks.core.data.TaskAttribute;
 import org.eclipse.mylyn.tasks.core.data.TaskData;
@@ -143,7 +144,8 @@ public abstract class AbstractTaskEditorPage extends FormPage implements ISelect
 		public void done(SubmitJobEvent event) {
 			final SubmitJob job = event.getJob();
 			PlatformUI.getWorkbench().getDisplay().asyncExec(new Runnable() {
-				private void openNewTask(AbstractTask newTask) {
+
+				private void openNewTask(ITask newTask) {
 					AbstractTaskContainer parent = null;
 					if (actionPart != null) {
 						parent = actionPart.getCategory();
@@ -188,11 +190,11 @@ public abstract class AbstractTaskEditorPage extends FormPage implements ISelect
 	private class TaskListChangeListener extends TaskListChangeAdapter {
 		@Override
 		public void containersChanged(Set<TaskContainerDelta> containers) {
-			AbstractTask taskToRefresh = null;
+			ITask taskToRefresh = null;
 			for (TaskContainerDelta taskContainerDelta : containers) {
 				if (task.equals(taskContainerDelta.getContainer())) {
 					if (taskContainerDelta.getKind().equals(TaskContainerDelta.Kind.CONTENT)) {
-						taskToRefresh = (AbstractTask) taskContainerDelta.getContainer();
+						taskToRefresh = (ITask) taskContainerDelta.getContainer();
 						break;
 					}
 				}
@@ -279,7 +281,7 @@ public abstract class AbstractTaskEditorPage extends FormPage implements ISelect
 
 	private SynchronizeEditorAction synchronizeEditorAction;
 
-	private AbstractTask task;
+	private ITask task;
 
 	private TaskData taskData;
 
@@ -580,7 +582,7 @@ public abstract class AbstractTaskEditorPage extends FormPage implements ISelect
 		toolBarManager.add(synchronizeEditorAction);
 
 		if (taskRepository != null && !taskData.isNew()) {
-			clearOutgoingAction = new ClearOutgoingAction(Collections.singletonList((AbstractTaskContainer) task));
+			clearOutgoingAction = new ClearOutgoingAction(Collections.singletonList((ITaskElement) task));
 			if (clearOutgoingAction.isEnabled()) {
 				toolBarManager.add(clearOutgoingAction);
 			}
@@ -667,7 +669,7 @@ public abstract class AbstractTaskEditorPage extends FormPage implements ISelect
 		return lastSelection;
 	}
 
-	public AbstractTask getTask() {
+	public ITask getTask() {
 		return task;
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditor.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditor.java
index 9a75d8fea..82329ae3f 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditor.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditor.java
@@ -50,7 +50,7 @@ import org.eclipse.mylyn.internal.tasks.ui.editors.TaskEditorActionContributor;
 import org.eclipse.mylyn.internal.tasks.ui.util.SelectionProviderAdapter;
 import org.eclipse.mylyn.internal.tasks.ui.util.TaskDragSourceListener;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.ui.AbstractRepositoryConnectorUi;
 import org.eclipse.swt.dnd.DND;
 import org.eclipse.swt.dnd.FileTransfer;
@@ -92,7 +92,7 @@ public class TaskEditor extends SharedHeaderFormEditor {
 
 	private IHyperlinkListener messageHyperLinkListener;
 
-	private AbstractTask task;
+	private ITask task;
 
 	private TaskEditorInput taskEditorInput;
 
@@ -572,7 +572,7 @@ public class TaskEditor extends SharedHeaderFormEditor {
 		}
 	}
 
-	private void updateHeaderLabel(AbstractTask task) {
+	private void updateHeaderLabel(ITask task) {
 		if (task instanceof LocalTask) {
 			getHeaderForm().getForm().setText("Task: " + task.getSummary());
 		} else {
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditorInput.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditorInput.java
index 16a59da1b..f893555a1 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditorInput.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/editors/TaskEditorInput.java
@@ -12,8 +12,9 @@ package org.eclipse.mylyn.tasks.ui.editors;
 
 import org.eclipse.core.runtime.Assert;
 import org.eclipse.jface.resource.ImageDescriptor;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.ui.editors.TaskEditorInputFactory;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
+import org.eclipse.mylyn.tasks.core.ITask;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.ui.IEditorInput;
@@ -33,14 +34,14 @@ public class TaskEditorInput implements IEditorInput, IPersistableElement {
 
 	private static final int MAX_LABEL_LENGTH = 60;
 
-	private final AbstractTask task;
+	private final ITask task;
 
 	private final TaskRepository taskRepository;
 
 	private Object data;
 
 	/**
-	 * @since 2.0
+	 * @since 3.0
 	 */
 	@Deprecated
 	public TaskEditorInput(AbstractTask task, boolean newTask) {
@@ -50,7 +51,7 @@ public class TaskEditorInput implements IEditorInput, IPersistableElement {
 	/**
 	 * @since 3.0
 	 */
-	public TaskEditorInput(TaskRepository taskRepository, AbstractTask task) {
+	public TaskEditorInput(TaskRepository taskRepository, ITask task) {
 		Assert.isNotNull(taskRepository);
 		Assert.isNotNull(task);
 		this.taskRepository = taskRepository;
@@ -145,8 +146,10 @@ public class TaskEditorInput implements IEditorInput, IPersistableElement {
 
 	/**
 	 * Returns the task if the task is in the task list; returns <code>null</code> otherwise.
+	 * 
+	 * @since 3.0
 	 */
-	public AbstractTask getTask() {
+	public ITask getTask() {
 		return task;
 	}
 
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractEditQueryWizard.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractEditQueryWizard.java
index ca5d04d73..79eb4baa6 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractEditQueryWizard.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractEditQueryWizard.java
@@ -9,10 +9,10 @@
 package org.eclipse.mylyn.tasks.ui.wizards;
 
 import org.eclipse.jface.wizard.Wizard;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 
@@ -34,6 +34,9 @@ public abstract class AbstractEditQueryWizard extends Wizard {
 
 	protected AbstractRepositoryQueryPage page;
 
+	/**
+	 * @since 3.0
+	 */
 	public AbstractEditQueryWizard(TaskRepository repository, AbstractRepositoryQuery query) {
 		this.repository = repository;
 		this.query = query;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractRepositoryQueryPage.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractRepositoryQueryPage.java
index 3f81356fb..eb64f1457 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractRepositoryQueryPage.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/AbstractRepositoryQueryPage.java
@@ -12,13 +12,13 @@ import java.util.Set;
 
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.wizard.WizardPage;
+import org.eclipse.mylyn.internal.tasks.core.AbstractRepositoryQuery;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.internal.tasks.core.TaskRepositoryManager;
 import org.eclipse.mylyn.internal.tasks.ui.ITasksUiConstants;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiImages;
 import org.eclipse.mylyn.internal.tasks.ui.search.SearchHitCollector;
 import org.eclipse.mylyn.tasks.core.AbstractRepositoryConnector;
-import org.eclipse.mylyn.tasks.core.AbstractRepositoryQuery;
-import org.eclipse.mylyn.tasks.core.AbstractTaskCategory;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;
 import org.eclipse.search.ui.ISearchPage;
diff --git a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/NewTaskWizard.java b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/NewTaskWizard.java
index 73c3ac2a8..098ccc6f1 100644
--- a/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/NewTaskWizard.java
+++ b/org.eclipse.mylyn.tasks.ui/src/org/eclipse/mylyn/tasks/ui/wizards/NewTaskWizard.java
@@ -18,6 +18,7 @@ import org.eclipse.jface.operation.IRunnableWithProgress;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.wizard.Wizard;
 import org.eclipse.mylyn.commons.core.StatusHandler;
+import org.eclipse.mylyn.internal.tasks.core.AbstractTask;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractAttributeFactory;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractLegacyRepositoryConnector;
 import org.eclipse.mylyn.internal.tasks.core.deprecated.AbstractTaskDataHandler;
@@ -26,7 +27,6 @@ import org.eclipse.mylyn.internal.tasks.core.deprecated.TaskSelection;
 import org.eclipse.mylyn.internal.tasks.ui.TasksUiPlugin;
 import org.eclipse.mylyn.internal.tasks.ui.deprecated.NewTaskEditorInput;
 import org.eclipse.mylyn.internal.tasks.ui.util.TasksUiInternal;
-import org.eclipse.mylyn.tasks.core.AbstractTask;
 import org.eclipse.mylyn.tasks.core.RepositoryStatus;
 import org.eclipse.mylyn.tasks.core.TaskRepository;
 import org.eclipse.mylyn.tasks.ui.TasksUi;