Bug 573987: [Toolsmiths] Properties Editor improvements (Perspective, Toolbar)

- open the editor on completion of the new properties context wizard
- remove toggle action for showing data contexts
- filter out inapplicable child/sibling creation actions for virtual
  nodes in the editor tree
- add preference for action to take on opening the Context Editor
- fix the tracking of state of the Preview View toggle button
- compute initial generator and source model in the wizard from
  the current workbench selection, where applicable

Change-Id: I20f40f34bc71ac6ea1b885aed6f5118ee97132ec
Signed-off-by: Christian W. Damus <give.a.damus@gmail.com>

28 files changed, 989 insertions, 385 deletions

diff --git a/plugins/infra/ui/org.eclipse.papyrus.infra.ui/META-INF/MANIFEST.MF b/plugins/infra/ui/org.eclipse.papyrus.infra.ui/META-INF/MANIFEST.MF
index 69d5d9722b8..9215e2ba831 100644
--- a/plugins/infra/ui/org.eclipse.papyrus.infra.ui/META-INF/MANIFEST.MF
+++ b/plugins/infra/ui/org.eclipse.papyrus.infra.ui/META-INF/MANIFEST.MF
@@ -45,7 +45,7 @@ Require-Bundle: org.eclipse.core.databinding;bundle-version="[1.9.0,2.0.0)",
  org.eclipse.ui.views.properties.tabbed;bundle-version="[3.8.0,4.0.0)",
  org.eclipse.uml2.types;bundle-version="[2.5.0,3.0.0)"
 Bundle-Vendor: %providerName
-Bundle-Version: 3.2.0.qualifier
+Bundle-Version: 3.3.0.qualifier
 Eclipse-BuddyPolicy: dependent
 Bundle-ManifestVersion: 2
 Bundle-Activator: org.eclipse.papyrus.infra.ui.Activator
diff --git a/plugins/infra/ui/org.eclipse.papyrus.infra.ui/pom.xml b/plugins/infra/ui/org.eclipse.papyrus.infra.ui/pom.xml
index 77ba081eec3..6a16c912371 100644
--- a/plugins/infra/ui/org.eclipse.papyrus.infra.ui/pom.xml
+++ b/plugins/infra/ui/org.eclipse.papyrus.infra.ui/pom.xml
@@ -9,7 +9,7 @@
 		<version>0.0.1-SNAPSHOT</version>
 	</parent>
 	<artifactId>org.eclipse.papyrus.infra.ui</artifactId>
-	<version>3.2.0-SNAPSHOT</version>
+	<version>3.3.0-SNAPSHOT</version>
 	<packaging>eclipse-plugin</packaging>
 	<description>Plugin dedicated to manage generic menus and actions, linked to EMF but not to UML nor GMF technologies.</description>
 </project>
\ No newline at end of file
diff --git a/plugins/infra/ui/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/util/EditorHelper.java b/plugins/infra/ui/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/util/EditorHelper.java
index feb1c50e5a8..67355d16c17 100644
--- a/plugins/infra/ui/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/util/EditorHelper.java
+++ b/plugins/infra/ui/org.eclipse.papyrus.infra.ui/src/org/eclipse/papyrus/infra/ui/util/EditorHelper.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2012, 2016 CEA LIST, Christian W. Damus, and others.
+ * Copyright (c) 2012, 2021 CEA LIST, Christian W. Damus, and others.
  *
  *
  * All rights reserved. This program and the accompanying materials
@@ -11,7 +11,7 @@
  *
  * Contributors:
  *  Vincent Lorenzo (CEA LIST) Vincent.Lorenzo@cea.fr - Initial API and implementation
- *  Christian W. Damus - bug 488965
+ *  Christian W. Damus - bugs 488965, 573987
  *
  *****************************************************************************/
 package org.eclipse.papyrus.infra.ui.util;
@@ -26,9 +26,9 @@ import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.PlatformUI;
 
 /**
+ * A helper that provides convenient access to the UI context of editors in a workbench,
+ * such as active window, part, editor, page, etc.
  *
- * a helper for the Editor
- * 
  * @since 1.2
  *
  */
@@ -40,9 +40,44 @@ public class EditorHelper {
 
 
 	/**
+	 * Obtain a specific helper instance for the given {@code workbench} that
+	 * makes the best effort to get results, even if they are not actually
+	 * active elements of the workbench.
+	 *
+	 * @param workbench
+	 *            the workbench
+	 *
+	 * @return the specific nest-effort helper instance for the {@code workbench}
+	 *
+	 * @since 3.3
+	 * @see #getInstance(IWorkbench, boolean)
+	 */
+	public static Instance getInstance(IWorkbench workbench) {
+		return getInstance(workbench, true);
+	}
+
+	/**
+	 * Obtain a specific helper instance for the given {@code workbench} that
+	 * optionally makes the best effort to get results, even if they are not
+	 * actually active elements of the workbench.
+	 *
+	 * @param workbench
+	 *            the workbench
+	 * @param bestEffort
+	 *            whether to make a best effort to get an element, even if none is actually active in the literal sense
+	 *
+	 * @return the specific helper instance for the {@code workbench}
+	 *
+	 * @since 3.3
+	 */
+	public static Instance getInstance(IWorkbench workbench, boolean bestEffort) {
+		return new Instance(workbench, bestEffort);
+	}
+
+	/**
 	 *
 	 * @return
-	 * 		the current workbench window or <code>null</code> if not found
+	 *         the current workbench window or <code>null</code> if not found
 	 */
 	public static final Shell getActiveShell() {
 		final IWorkbench workbench = PlatformUI.getWorkbench();
@@ -55,7 +90,7 @@ public class EditorHelper {
 	/**
 	 *
 	 * @return
-	 * 		the current workbench window or <code>null</code> if not found
+	 *         the current workbench window or <code>null</code> if not found
 	 */
 	public static final IWorkbenchWindow getActiveWindow() {
 		final IWorkbench workbench = PlatformUI.getWorkbench();
@@ -68,7 +103,7 @@ public class EditorHelper {
 	/**
 	 *
 	 * @return
-	 * 		the current editor or <code>null</code> if not found
+	 *         the current editor or <code>null</code> if not found
 	 */
 	public static final IEditorPart getCurrentEditor() {
 		final IWorkbench workbench = PlatformUI.getWorkbench();
@@ -87,7 +122,7 @@ public class EditorHelper {
 	/**
 	 *
 	 * @return
-	 * 		the current active part or <code>null</code> if not found
+	 *         the current active part or <code>null</code> if not found
 	 */
 	public static final IWorkbenchPart getActivePart() {
 		final IWorkbench workbench = PlatformUI.getWorkbench();
@@ -102,4 +137,110 @@ public class EditorHelper {
 		}
 		return null;
 	}
+
+	//
+	// Nested types
+	//
+
+	/**
+	 * A specific editor-helper instance for a workbench.
+	 *
+	 * @since 3.3
+	 */
+	public static final class Instance {
+
+		private final IWorkbench workbench;
+		private final boolean bestEffort;
+
+		private Instance(IWorkbench workbench, boolean bestEffort) {
+			super();
+
+			this.workbench = workbench;
+			this.bestEffort = bestEffort;
+		}
+
+		/**
+		 * Get the currently active workbench window shell, or whatever is the display's
+		 * active shell if no workbench window actually is active.
+		 *
+		 * @return the current active shell
+		 */
+		public Shell getActiveShell() {
+			IWorkbenchWindow window = getActiveWindow();
+			return (window == null) ? Display.getCurrent().getActiveShell() : window.getShell();
+		}
+
+		/**
+		 * Get the currently active workbench window, or the first available window as a best-effort
+		 * guess if applicable.
+		 *
+		 * @return the active workbench window, or a best-effort guess if I am so configured
+		 */
+		public IWorkbenchWindow getActiveWindow() {
+			if (workbench == null) {
+				return null;
+			}
+
+			IWorkbenchWindow result = workbench.getActiveWorkbenchWindow();
+
+			if (result == null && bestEffort && workbench.getWorkbenchWindowCount() > 0) {
+				// There isn't actually an active page. So just get some page
+				result = workbench.getWorkbenchWindows()[0];
+			}
+
+			return result;
+		}
+
+		/**
+		 * Get the currently active workbench page, or the first available page as a best-effort
+		 * guess if applicable.
+		 *
+		 * @return the active workbench page, or a best-effort guess if I am so configured
+		 */
+		public IWorkbenchPage getActivePage() {
+			IWorkbenchPage result = null;
+
+			IWorkbenchWindow window = getActiveWindow();
+			if (window != null) {
+				result = window.getActivePage();
+				if (result == null && bestEffort) {
+					// It's not active. Just get some page
+					IWorkbenchPage[] pages = window.getPages();
+					if (pages.length > 0) {
+						result = pages[0];
+					}
+				}
+			}
+
+			return result;
+		}
+
+		/**
+		 * Get the currently active editor, if any, in the currently active {@linkplain #getActivePage() workbench page}.
+		 *
+		 * @return the active editor in the active page, or {@code null} if either the active page has no active editor or
+		 *         an active page could not be determined
+		 *
+		 * @see #getActivePage()
+		 */
+		public IEditorPart getActiveEditor() {
+			IWorkbenchPage page = getActivePage();
+			return (page == null) ? null : page.getActiveEditor();
+		}
+
+		/**
+		 * Get the currently active part, if any, in the currently active {@linkplain #getActivePage() workbench page}.
+		 *
+		 * @return the active part in the active page, or {@code null} if either the active page has no active part or
+		 *         an active page could not be determined
+		 *
+		 * @see #getActivePage()
+		 */
+		public IWorkbenchPart getActivePart() {
+			IWorkbenchPage page = getActivePage();
+			return (page == null) ? null : page.getActivePart();
+		}
+
+	}
+
 }
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/META-INF/MANIFEST.MF b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/META-INF/MANIFEST.MF
index 053d6a71522..4a1aff57ecb 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/META-INF/MANIFEST.MF
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/META-INF/MANIFEST.MF
@@ -27,7 +27,8 @@ Require-Bundle: org.eclipse.core.databinding.property;bundle-version="[1.8.0,2.0
  org.eclipse.papyrus.views.properties.toolsmiths;bundle-version="[3.0.0,4.0.0)",
  org.eclipse.ui.views.properties.tabbed;bundle-version="[3.8.0,4.0.0)",
  org.eclipse.uml2.uml;bundle-version="[5.5.0,6.0.0)",
- org.eclipse.papyrus.emf.facet.custom.ui;bundle-version="[4.0.0,5.0.0)"
+ org.eclipse.papyrus.emf.facet.custom.ui;bundle-version="[4.0.0,5.0.0)",
+ org.eclipse.papyrus.infra.ui;bundle-version="[3.3.0,4.0.0)"
 Bundle-Vendor: %Bundle-Vendor
 Bundle-ActivationPolicy: lazy
 Bundle-ClassPath: .,
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/EcoreGenerator.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/EcoreGenerator.java
index 40cacd80a4c..712f9f0fb06 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/EcoreGenerator.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/EcoreGenerator.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2019  CEA LIST.
+ * Copyright (c) 2010, 2021  CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -12,6 +12,7 @@
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Thibault Le Ouay t.leouay@sherpa-eng.com - Strategy improvement of generated files
  *  Vincent Lorenzo (CEA LIST) vincent.lorenzo@cea.fr - Bug 544869
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.generators;
 
@@ -25,6 +26,9 @@ import java.util.List;
 import java.util.Set;
 
 import org.eclipse.core.databinding.observable.value.IObservableValue;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.emf.common.notify.Notifier;
 import org.eclipse.emf.common.util.TreeIterator;
 import org.eclipse.emf.common.util.URI;
@@ -36,6 +40,7 @@ import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EPackage;
 import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EStructuralFeature;
+import org.eclipse.emf.ecore.EcorePackage;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.m2m.qvt.oml.BasicModelExtent;
 import org.eclipse.m2m.qvt.oml.ModelExtent;
@@ -68,7 +73,7 @@ public class EcoreGenerator extends AbstractQVTGenerator {
 	protected List<EPackage> listEPackages;
 
 	@Override
-	public void createControls(Composite parent) {
+	public void createControls(Composite parent, IFile workbenchSelection) {
 		Composite root = new Composite(parent, SWT.NONE);
 		GridLayout layout = new GridLayout(2, false);
 		layout.marginWidth = 0;
@@ -86,6 +91,12 @@ public class EcoreGenerator extends AbstractQVTGenerator {
 
 		listEPackages = new ArrayList<>();
 
+		if (workbenchSelection != null) {
+			IFile suggestion = getSourceFile(workbenchSelection);
+			if (suggestion != null) {
+				sourceFileChooser.setFile(suggestion);
+			}
+		}
 	}
 
 	@Override
@@ -393,6 +404,15 @@ public class EcoreGenerator extends AbstractQVTGenerator {
 
 	}
 
+	@Override
+	public IFile getSourceFile(IFile file, IContentType contentType) {
+		if (contentType == null) {
+			return null; // Ecore content type is registered, so the file is not an Ecore model
+		}
+
+		IContentType ecore = Platform.getContentTypeManager().getContentType(EcorePackage.eCONTENT_TYPE);
 
+		return ecore != null && contentType.isKindOf(ecore) ? file : null;
+	}
 
 }
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/IGenerator.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/IGenerator.java
index 38b3cd6b45a..80410535140 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/IGenerator.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/IGenerator.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2014 CEA LIST and others.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -12,14 +12,21 @@
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Thibault Le Ouay t.leouay@sherpa-eng.com - Strategy improvement of generated files
  *  Christian W. Damus (CEA) - bug 422257
+ *  Christian W. Damus - bug 573987
  *
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.generators;
 
 import java.util.List;
+import java.util.Optional;
 
 import org.eclipse.core.databinding.observable.value.IObservableValue;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.content.IContentDescription;
+import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.emf.common.util.URI;
+import org.eclipse.papyrus.customization.properties.generation.Activator;
 import org.eclipse.papyrus.infra.properties.contexts.Context;
 import org.eclipse.papyrus.infra.properties.contexts.DataContextElement;
 import org.eclipse.papyrus.infra.properties.contexts.Property;
@@ -54,8 +61,29 @@ public interface IGenerator {
 	 *
 	 * @param parent
 	 *            The Composite in which the controls will be displayed
+	 *
+	 * @deprecated Implement the {@link #createControls(Composite, IFile)} method, instead
+	 */
+	@Deprecated
+	public default void createControls(Composite parent) {
+		// Extant classes already override this. New ones should not
+		throw new AbstractMethodError("createControls(Composite)"); //$NON-NLS-1$
+	}
+
+	/**
+	 * Creates the controls for this Generator. The generator is responsible
+	 * for displaying any Control useful for editing its options, and listening
+	 * for changes on them.
+	 *
+	 * @param parent
+	 *            The Composite in which the controls will be displayed
+	 * @param workbenchSelection
+	 *            the file currently selected in the workbench, if any.
+	 *            May be {@code null}
 	 */
-	public void createControls(Composite parent);
+	public default void createControls(Composite parent, IFile workbenchSelection) {
+		createControls(parent);
+	}
 
 	/**
 	 * Gets the description for this Generator
@@ -148,4 +176,60 @@ public interface IGenerator {
 	 */
 	public void dispose();
 
+	/**
+	 * Query the preferred source model for generation of a <em>Properties Context</em> model based on
+	 * the given file selection in the workbench.
+	 *
+	 * @param file
+	 *            the file selection in the workbench
+	 * @param contentType
+	 *            the content type of the {@code file}. May be {@code null} if the content type cannot
+	 *            be determined or if the {@code file}'s content type is not registered in the platform
+	 * @return the preferred file to use as input for the generation. This should be related in some way to
+	 *         the selected {@code file}, usually being that {@code file} itself. Or else {@code null} to indicate
+	 *         that the given {@code file} is not handled at all by this generator
+	 *
+	 * @see #getSourceFile(IFile, IContentType)
+	 */
+	public default IFile getSourceFile(IFile file) {
+		try {
+			Optional<IContentType> contentType = Optional.ofNullable(file.getContentDescription()).map(IContentDescription::getContentType);
+			return getSourceFile(file, contentType.orElse(null));
+		} catch (CoreException e) {
+			Activator.log.error("Could not determine content type of " + file, e); //$NON-NLS-1$
+			return null;
+		}
+	}
+
+	/**
+	 * Query the preferred source model for generation of a <em>Properties Context</em> model based on
+	 * the given file selection in the workbench.
+	 *
+	 * @param file
+	 *            the file selection in the workbench
+	 * @param contentType
+	 *            the content type of the {@code file}. May be {@code null} if the content type cannot
+	 *            be determined or if the {@code file}'s content type is not registered in the platform
+	 * @return the preferred file to use as input for the generation. This should be related in some way to
+	 *         the selected {@code file}, usually being that {@code file} itself. Or else {@code null} to indicate
+	 *         that the given {@code file} is not handled at all by this generator
+	 */
+	public default IFile getSourceFile(IFile file, IContentType contentType) {
+		return null;
+	}
+
+	/**
+	 * Query whether I can generate a <em>Properties Context</em> model from the given file selected in the workbench.
+	 *
+	 * @param selectedFile
+	 *            the file currently selected in the workbench. Must not be {@code null}
+	 * @param contentType
+	 *            the content type of the selected file. May be {@code null} if the content type cannot
+	 *            be determined or if the selected file's content type is not registered in the platform
+	 * @return
+	 */
+	public default boolean canGenerate(IFile selectedFile, IContentType contentType) {
+		return getSourceFile(selectedFile, contentType) != null;
+	}
+
 }
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/ProfileGenerator.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/ProfileGenerator.java
index 9a894763f7e..4a6291a1d54 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/ProfileGenerator.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/generators/ProfileGenerator.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010 CEA LIST.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -11,6 +11,7 @@
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Thibault Le Ouay t.leouay@sherpa-eng.com - Strategy improvement of generated files
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.generators;
 
@@ -24,6 +25,9 @@ import java.util.List;
 import java.util.Set;
 
 import org.eclipse.core.databinding.observable.value.IObservableValue;
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.runtime.Platform;
+import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.emf.common.util.TreeIterator;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.EObject;
@@ -33,6 +37,7 @@ import org.eclipse.m2m.qvt.oml.ModelExtent;
 import org.eclipse.papyrus.customization.properties.generation.Activator;
 import org.eclipse.papyrus.customization.properties.generation.messages.Messages;
 import org.eclipse.papyrus.customization.properties.generation.wizard.widget.FileChooser;
+import org.eclipse.papyrus.infra.core.resource.sasheditor.DiModel;
 import org.eclipse.papyrus.infra.properties.contexts.Context;
 import org.eclipse.papyrus.infra.properties.contexts.DataContextElement;
 import org.eclipse.papyrus.infra.properties.contexts.Property;
@@ -51,6 +56,8 @@ import org.eclipse.uml2.uml.Package;
 import org.eclipse.uml2.uml.PackageImport;
 import org.eclipse.uml2.uml.PrimitiveType;
 import org.eclipse.uml2.uml.Profile;
+import org.eclipse.uml2.uml.UMLPackage;
+import org.eclipse.uml2.uml.resource.UMLResource;
 
 /**
  * An IGenerator for building Contexts from a UML Profile
@@ -71,7 +78,7 @@ public class ProfileGenerator extends AbstractQVTGenerator {
 
 
 	@Override
-	public void createControls(Composite parent) {
+	public void createControls(Composite parent, IFile workbenchSelection) {
 		Composite root = new Composite(parent, SWT.NONE);
 		GridLayout layout = new GridLayout(2, false);
 		layout.marginWidth = 0;
@@ -87,6 +94,13 @@ public class ProfileGenerator extends AbstractQVTGenerator {
 		sourceFileChooser.setFilterExtensions(FileExtensions.umlProfileExtensions);
 		sourceFileChooser.addListener(this);
 		listEObject = new ArrayList<>();
+
+		if (workbenchSelection != null) {
+			IFile suggestion = getSourceFile(workbenchSelection);
+			if (suggestion != null) {
+				sourceFileChooser.setFile(suggestion);
+			}
+		}
 	}
 
 	@Override
@@ -371,4 +385,27 @@ public class ProfileGenerator extends AbstractQVTGenerator {
 		return null;
 
 	}
+
+	@Override
+	public IFile getSourceFile(IFile file, IContentType contentType) {
+		IFile result = null;
+
+		if (DiModel.DI_FILE_EXTENSION.equals(file.getFileExtension())) {
+			// Get the associated UML file, if it exists
+			IFile umlFile = file.getProject().getFile(file.getProjectRelativePath().removeFileExtension().addFileExtension(UMLResource.FILE_EXTENSION));
+			if (umlFile != null && umlFile.isAccessible()) {
+				result = getSourceFile(umlFile);
+			}
+		} else if (contentType != null) {
+			// The only other supported input is the UML file, itself, and the UML content type is registered
+			IContentType uml = Platform.getContentTypeManager().getContentType(UMLPackage.eCONTENT_TYPE);
+
+			if (uml != null && contentType.isKindOf(uml)) {
+				result = file;
+			}
+		}
+
+		return result;
+	}
+
 }
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextMainPage.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextMainPage.java
index 1db719f14be..d049c4a1772 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextMainPage.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextMainPage.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2014 CEA LIST and others.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -12,13 +12,19 @@
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Thibault Le Ouay t.leouay@sherpa-eng.com - Add SelectOutputPage
  *  Christian W. Damus (CEA) - bug 422257
+ *  Christian W. Damus - bug 573987
  *
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.wizard;
 
 import java.util.List;
 
+import org.eclipse.core.resources.IFile;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.content.IContentDescription;
+import org.eclipse.core.runtime.content.IContentType;
 import org.eclipse.jface.wizard.IWizardPage;
+import org.eclipse.papyrus.customization.properties.generation.Activator;
 import org.eclipse.papyrus.customization.properties.generation.extensionpoint.GeneratorExtensionPoint;
 import org.eclipse.papyrus.customization.properties.generation.generators.IGenerator;
 import org.eclipse.papyrus.customization.properties.generation.messages.Messages;
@@ -64,6 +70,7 @@ public class CreateContextMainPage extends AbstractCreateContextPage implements
 		}
 	}
 
+	@Override
 	public void createControl(Composite parent) {
 		Composite root = new Composite(parent, SWT.NONE);
 		root.setLayout(new GridLayout(1, false));
@@ -80,6 +87,8 @@ public class CreateContextMainPage extends AbstractCreateContextPage implements
 
 		setControl(root);
 		setDescription(Messages.CreateContextMainPage_description);
+
+		getWizard().getCurrentlySelectedFile().ifPresent(this::selectGenerator);
 	}
 
 	@Override
@@ -90,8 +99,32 @@ public class CreateContextMainPage extends AbstractCreateContextPage implements
 		return getWizard().generatorPage;
 	}
 
+	@Override
 	public void handleEvent(Event event) {
 		super.setPageComplete(true);
 	}
 
+	/**
+	 * Select the best-fitting generator, if any, for the file currently selected
+	 * in the workbench.
+	 *
+	 * @param selectedFile
+	 *            the currently selected file. Must not be {@code null}
+	 */
+	private void selectGenerator(IFile selectedFile) {
+		IContentType contentType = null;
+
+		try {
+			IContentDescription description = selectedFile.getContentDescription();
+			contentType = (description != null) ? description.getContentType() : null;
+		} catch (CoreException e) {
+			Activator.log.error("Failed to determine content type of " + selectedFile, e); //$NON-NLS-1$
+		}
+
+		IContentType _contentType = contentType;
+		generators.stream().filter(gen -> gen.canGenerate(selectedFile, _contentType))
+				.findFirst()
+				.ifPresent(gen -> combo.select(generators.indexOf(gen)));
+	}
+
 }
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextWizard.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextWizard.java
index 0c61bcc3f91..5b71bd56090 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextWizard.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/CreateContextWizard.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2015, 2017 CEA LIST, Christian W. Damus, and others.
+ * Copyright (c) 2010, 2021, 2017 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -11,11 +11,13 @@
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Christian W. Damus (CEA) - bug 422257
- *  Christian W. Damus - bug 482927
- *  Vincent Lorenzo (CEA LIST) - bug 520271 
+ *  Christian W. Damus - bugs 482927, 573987
+ *  Vincent Lorenzo (CEA LIST) - bug 520271
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.wizard;
 
+import static java.util.stream.StreamSupport.stream;
+
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
@@ -25,11 +27,16 @@ import java.util.HashSet;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 
+import org.eclipse.core.resources.IFile;
 import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.emf.common.util.URI;
 import org.eclipse.emf.ecore.xmi.XMLResource;
 import org.eclipse.jface.operation.IRunnableWithProgress;
+import org.eclipse.jface.util.Policy;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.wizard.Wizard;
 import org.eclipse.papyrus.customization.properties.generation.Activator;
@@ -40,6 +47,7 @@ import org.eclipse.papyrus.customization.properties.generation.generators.IGener
 import org.eclipse.papyrus.customization.properties.generation.layout.ILayoutGenerator;
 import org.eclipse.papyrus.customization.properties.generation.messages.Messages;
 import org.eclipse.papyrus.customization.properties.generation.wizard.widget.TernaryButton;
+import org.eclipse.papyrus.infra.emf.utils.ResourceUtils;
 import org.eclipse.papyrus.infra.properties.contexts.Context;
 import org.eclipse.papyrus.infra.properties.contexts.ContextsFactory;
 import org.eclipse.papyrus.infra.properties.contexts.DataContextElement;
@@ -52,8 +60,12 @@ import org.eclipse.papyrus.infra.properties.ui.UiFactory;
 import org.eclipse.papyrus.infra.properties.ui.ValueAttribute;
 import org.eclipse.papyrus.infra.properties.ui.runtime.IConfigurationManager;
 import org.eclipse.papyrus.infra.properties.ui.runtime.PropertiesRuntime;
+import org.eclipse.papyrus.infra.ui.util.EditorHelper;
 import org.eclipse.ui.INewWizard;
 import org.eclipse.ui.IWorkbench;
+import org.eclipse.ui.IWorkbenchPage;
+import org.eclipse.ui.PartInitException;
+import org.eclipse.ui.ide.IDE;
 
 /**
  * A Wizard for generating Property view contexts
@@ -87,14 +99,20 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 	 */
 	protected ILayoutGenerator layoutGenerator;
 
+	private IWorkbenchPage workbenchPage;
+
+	private Optional<IFile> currentlySelectedFile;
+
 	public CreateContextWizard() {
 		setDefaultPageImageDescriptor(Activator.getDefault().getImageDescriptor("/icons/wizban-custom.png")); //$NON-NLS-1$
 	}
 
 	@Override
 	public boolean performFinish() {
+		boolean result = false;
+
 		if (generator == null || contexts == null || contexts.isEmpty() || layoutGenerator == null) {
-			return false;
+			return result;
 		}
 
 		IConfigurationManager configManager = PropertiesRuntime.getConfigurationManager();
@@ -124,9 +142,9 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 					continue;
 				}
 
-				List<PropertyEditor> editors = new LinkedList<PropertyEditor>();
+				List<PropertyEditor> editors = new LinkedList<>();
 				// the list of properties for the current view
-				final List<Property> properties = new ArrayList<Property>();
+				final List<Property> properties = new ArrayList<>();
 				for (DataContextElement element : getAllContextElements(view.getDatacontexts())) {
 					for (Property property : element.getProperties()) {
 						if (isSelected(fieldSelection, property, view.getElementMultiplicity() != 1)) {
@@ -135,9 +153,9 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 					}
 				}
 
-				final List<Property> tmpProperties = new ArrayList<Property>(properties);
+				final List<Property> tmpProperties = new ArrayList<>(properties);
 				for (Property p1 : tmpProperties) {
-					//Bug 519090
+					// Bug 519090
 					// we remove all redefined properties from the list
 					properties.removeAll(p1.getRedefinedProperties());
 				}
@@ -169,11 +187,12 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 				setNeedsProgressMonitor(true);
 				final Context currentContext = context;
 
-				final Map<String, Object> saveOptions = new HashMap<String, Object>();
+				final Map<String, Object> saveOptions = new HashMap<>();
 				saveOptions.put(XMLResource.OPTION_PROCESS_DANGLING_HREF, XMLResource.OPTION_PROCESS_DANGLING_HREF_RECORD);
 
 				getContainer().run(true, true, new IRunnableWithProgress() {
 
+					@Override
 					public void run(IProgressMonitor monitor) throws InvocationTargetException, InterruptedException {
 						monitor.beginTask(Messages.CreateContextWizard_propertyViewGenerationJobName + currentContext.getUserLabel(), numberOfSections + 1);
 						monitor.worked(1);
@@ -204,9 +223,24 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 				Activator.log.error(ex);
 			}
 
+			result = true;
 		}
 
-		return true;
+		if (result) {
+			// Open the "main" generated context file
+			URI uriToOpen = contexts.get(0).eResource().getURI();
+			if (uriToOpen.isPlatformResource()) {
+				IFile file = ResourceUtils.getFile(contexts.get(0).eResource());
+
+				try {
+					IDE.openEditor(workbenchPage, file);
+				} catch (PartInitException e) {
+					Policy.getStatusHandler().show(e.getStatus(), getWindowTitle());
+				}
+			}
+		}
+
+		return result;
 	}
 
 	private boolean isSelected(FieldSelection fieldSelection, Property property, boolean multiple) {
@@ -276,7 +310,7 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 	protected List<String> getPropertyPath(DataContextElement element) {
 		List<String> result;
 		if (element.getPackage() == null) {
-			result = new LinkedList<String>();
+			result = new LinkedList<>();
 		} else {
 			result = getPropertyPath(element.getPackage());
 		}
@@ -285,7 +319,7 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 	}
 
 	private Set<DataContextElement> getAllContextElements(Collection<DataContextElement> source) {
-		Set<DataContextElement> result = new HashSet<DataContextElement>();
+		Set<DataContextElement> result = new HashSet<>();
 		for (DataContextElement element : source) {
 			getAllContextElements(element, result);
 		}
@@ -303,21 +337,36 @@ public class CreateContextWizard extends Wizard implements INewWizard {
 		}
 	}
 
+	@Override
 	public void init(IWorkbench workbench, IStructuredSelection selection) {
 		addPage(mainPage = new CreateContextMainPage());
 		addPage(generatorPage = new GeneratorPage());
 		addPage(selectOutputPage = new SelectOutputPage());
 		addPage(selectFieldsPage = new SelectFieldsPage());
-		// addPage(layout = new LayoutPage());
 
 		setWindowTitle(Messages.CreateContextWizard_pageTitle);
 
+		workbenchPage = EditorHelper.getInstance(workbench).getActivePage();
+		currentlySelectedFile = stream(((Iterable<?>) selection).spliterator(), false)
+				.filter(IFile.class::isInstance).map(IFile.class::cast)
+				.findFirst();
+	}
+
+	/**
+	 * Query the file that was selected in the workbench when the user launched the wizard.
+	 *
+	 * @return the currently selected file
+	 */
+	Optional<IFile> getCurrentlySelectedFile() {
+		return currentlySelectedFile;
 	}
 
 	protected void setGenerator(IGenerator generator) {
-		this.generator = generator;
-		generatorPage.setGenerator(generator);
-		generatorPage.doBinding();
+		if (!Objects.equals(this.generator, generator)) {
+			this.generator = generator;
+			generatorPage.setGenerator(generator);
+			generatorPage.doBinding();
+		}
 	}
 
 	protected void setContexts(List<Context> contexts) {
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/GeneratorPage.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/GeneratorPage.java
index 41423893f01..abe06fe6e7e 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/GeneratorPage.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/GeneratorPage.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2014 CEA LIST and others.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -12,6 +12,7 @@
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Thibault Le Ouay t.leouay@sherpa-eng.com - Strategy improvement of generated files
  *  Christian W. Damus (CEA) - bug 422257
+ *  Christian W. Damus - bug 573987
  *
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.wizard;
@@ -23,8 +24,6 @@ import org.eclipse.core.databinding.DataBindingContext;
 import org.eclipse.core.databinding.UpdateValueStrategy;
 import org.eclipse.core.databinding.conversion.IConverter;
 import org.eclipse.core.databinding.observable.value.IObservableValue;
-import org.eclipse.core.databinding.observable.value.IValueChangeListener;
-import org.eclipse.core.databinding.observable.value.ValueChangeEvent;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.emf.common.util.URI;
 import org.eclipse.jface.databinding.wizard.WizardPageSupport;
@@ -110,7 +109,7 @@ public class GeneratorPage extends AbstractCreateContextPage implements Listener
 
 		setDescription(generator.getDescription());
 		this.generator = generator;
-		generator.createControls(generatorControl);
+		generator.createControls(generatorControl, getWizard().getCurrentlySelectedFile().orElse(null));
 		generatorControl.layout();
 		srcTextObservable = this.generator.getObservableValue();
 		root.layout();
@@ -284,26 +283,26 @@ public class GeneratorPage extends AbstractCreateContextPage implements Listener
 			targetFieldStrategy.setAfterConvertValidator(srcValidator);
 			binding = ctx.bindValue(srcTextObservable, targetTextObservable, srcFieldStrategy, targetFieldStrategy);
 
-		}
-	}
-
-	@Override
-	public boolean canFlipToNextPage() {
-		binding.getValidationStatus().addValueChangeListener(new IValueChangeListener() {
-
-			@Override
-			public void handleValueChange(ValueChangeEvent event) {
-				IStatus status = (IStatus) event.diff.getNewValue();
+			binding.getValidationStatus().addValueChangeListener(event -> {
+				IStatus status = event.diff.getNewValue();
 				if (status.isOK() || status.getSeverity() == IStatus.WARNING) {
 					setNext(true);
 				} else {
 					setNext(false);
 				}
-			}
-
-		});
+			});
 
+			// The source file is the "target", which the binding would not normally update to the "model."
+			// But if the source file is already suggested, then we do want to initialize the output file
+			// from it, so update the "target" to the "model" in binding-speak
+			if (srcTextObservable.getValue() != null && !"".equals(srcTextObservable.getValue())) {
+				binding.updateTargetToModel();
+			}
+		}
+	}
 
+	@Override
+	public boolean canFlipToNextPage() {
 		return this.next;
 	}
 
diff --git a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/widget/FileChooser.java b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/widget/FileChooser.java
index 39750946bbb..1c4767cabdd 100644
--- a/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/widget/FileChooser.java
+++ b/plugins/uml/properties/org.eclipse.papyrus.uml.properties.generation/src/org/eclipse/papyrus/customization/properties/generation/wizard/widget/FileChooser.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010 CEA LIST.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,6 +10,7 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.customization.properties.generation.wizard.widget;
 
@@ -18,13 +19,14 @@ import java.util.HashSet;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 
 import org.eclipse.core.databinding.observable.value.IObservableValue;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.emf.common.ui.dialogs.WorkspaceResourceDialog;
 import org.eclipse.jface.databinding.swt.IWidgetValueProperty;
-import org.eclipse.jface.databinding.swt.WidgetProperties;
+import org.eclipse.jface.databinding.swt.typed.WidgetProperties;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ViewerFilter;
 import org.eclipse.jface.window.Window;
@@ -66,6 +68,8 @@ public class FileChooser extends Composite implements SelectionListener, Listene
 
 	private boolean newFile;
 
+	private IObservableValue<String> textObservable;
+
 	/**
 	 * Constructs a new FileChooser in the given Composite
 	 *
@@ -89,6 +93,9 @@ public class FileChooser extends Composite implements SelectionListener, Listene
 		browse.setText(Messages.FileChooser_browseWorkspace);
 		browse.addSelectionListener(this);
 		this.newFile = newFile;
+
+		IWidgetValueProperty<Text, String> prop = WidgetProperties.text(SWT.Modify);
+		textObservable = prop.observeDelayed(600, text);
 	}
 
 	/**
@@ -207,9 +214,7 @@ public class FileChooser extends Composite implements SelectionListener, Listene
 		if (result.length > 0) {
 			Object file = result[0];
 			if (file instanceof IFile) {
-				this.currentFile = ((IFile) file);
-				text.setText(currentFile.getFullPath().toString());
-				notifyChange();
+				setFile((IFile) file);
 			}
 		}
 	}
@@ -226,11 +231,32 @@ public class FileChooser extends Composite implements SelectionListener, Listene
 	}
 
 	public IObservableValue getObservableValue() {
-		IWidgetValueProperty prop = WidgetProperties.text(SWT.Modify);
-		return prop.observeDelayed(600, text);
+		return textObservable;
 	}
 
 	public void setText(String s) {
 		text.setText(s);
 	}
+
+	/**
+	 * Set the currently selected file.
+	 *
+	 * @param file
+	 *            the currently selected file. May be {@code null} to clear the selection
+	 */
+	public void setFile(IFile file) {
+		if (!Objects.equals(file, currentFile) && !text.isDisposed()) {
+			currentFile = file;
+			if (file == null) {
+				text.setText(""); //$NON-NLS-1$
+			} else {
+				text.setText(file.getFullPath().toString());
+			}
+
+			// Trigger the update immediately
+			getObservableValue().getValue();
+
+			notifyChange();
+		}
+	}
 }
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/META-INF/MANIFEST.MF b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/META-INF/MANIFEST.MF
index dccb834864b..75072e0473f 100755
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/META-INF/MANIFEST.MF
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/META-INF/MANIFEST.MF
@@ -33,7 +33,7 @@ Bundle-Vendor: %Bundle-Vendor
 Bundle-ActivationPolicy: lazy
 Bundle-ClassPath: .,
  bin
-Bundle-Version: 3.1.0.qualifier
+Bundle-Version: 3.2.0.qualifier
 Bundle-Name: %Bundle-Name
 Bundle-Activator: org.eclipse.papyrus.views.properties.toolsmiths.Activator
 Bundle-ManifestVersion: 2
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/plugin.xml b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/plugin.xml
index c76e83ff3f1..f9ccef435d4 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/plugin.xml
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/plugin.xml
@@ -97,10 +97,6 @@
             class="org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.TogglePreviewAction"
             commandId="org.eclipse.papyrus.customization.properties.TogglePreview">
       </handler>
-      <handler
-            class="org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.ToggleDataContextAction"
-            commandId="org.eclipse.papyrus.customization.properties.ToggleDataContext">
-      </handler>
    </extension>
    <extension
          point="org.eclipse.ui.commands">
@@ -114,19 +110,10 @@
             id="org.eclipse.papyrus.customization.properties.TogglePreview"
             name="%command.name.0">
          <state
-               class="org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.TogglePreviewState"
+               class="org.eclipse.jface.commands.ToggleState"
                id="org.eclipse.ui.commands.toggleState">
          </state>
       </command>
-      <command
-            description="%command.description.1"
-            id="org.eclipse.papyrus.customization.properties.ToggleDataContext"
-            name="%command.name.1">
-            <state
-               class="org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.ToggleDataContextState"
-               id="org.eclipse.papyrus.customizatio.propertiesn.displayContextState">
-         </state>
-      </command>
    </extension>
    <extension
          point="org.eclipse.ui.menus">
@@ -169,22 +156,6 @@
                   </with>
                </visibleWhen>
             </command>
-            <command
-                  commandId="org.eclipse.papyrus.customization.properties.ToggleDataContext"
-                  icon="icons/DataContexts.gif"
-                  id="org.eclipse.papyrus.customization.properties.toggleDataContext"
-                  label="%command.label.0"
-                  style="toggle"
-                  tooltip="%command.tooltip.0">
-               <visibleWhen>
-                  <with
-                        variable="activeEditorId">
-                     <equals
-                           value="org.eclipse.papyrus.customization.properties.UIEditor">
-                     </equals>
-                  </with>
-               </visibleWhen>
-            </command>
          </toolbar>
       </menuContribution>
    </extension>
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/pom.xml b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/pom.xml
index 6f5f61ec653..76c7ed54449 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/pom.xml
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/pom.xml
@@ -13,6 +13,6 @@
 		<relativePath>../../../toolsmiths/pom.xml</relativePath>
 	</parent>
 	<artifactId>org.eclipse.papyrus.views.properties.toolsmiths</artifactId>
-	<version>3.1.0-SNAPSHOT</version>
+	<version>3.2.0-SNAPSHOT</version>
 	<packaging>eclipse-plugin</packaging>
 </project>
\ No newline at end of file
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/ContextEditorActionBarContributor.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/ContextEditorActionBarContributor.java
index 8e30244da7e..974e0dfc54f 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/ContextEditorActionBarContributor.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/ContextEditorActionBarContributor.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010 CEA LIST.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,6 +10,7 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.editor;
 
@@ -26,6 +27,7 @@ import org.eclipse.emf.edit.ui.action.DeleteAction;
 import org.eclipse.emf.edit.ui.action.PasteAction;
 import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.action.IMenuManager;
+import org.eclipse.jface.action.MenuManager;
 import org.eclipse.jface.viewers.ISelection;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
@@ -39,8 +41,8 @@ import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.MoDiscoCop
 import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.MoDiscoCutAction;
 import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.MoDiscoDeleteAction;
 import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.MoDiscoPasteAction;
-import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.ToggleDataContextAction;
 import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.ValidationAction;
+import org.eclipse.papyrus.views.properties.toolsmiths.messages.Messages;
 import org.eclipse.papyrus.views.properties.toolsmiths.util.ActionUtil;
 
 /**
@@ -52,8 +54,11 @@ import org.eclipse.papyrus.views.properties.toolsmiths.util.ActionUtil;
  */
 public class ContextEditorActionBarContributor extends EcoreActionBarContributor {
 
+	private static final String MENU_ID = "org.eclipse.papyrus.views.properties.toolsmiths.editor.menu"; //$NON-NLS-1$
 	private int i = 0;
 
+	private final ActionUtil actionUtil;
+
 	/**
 	 *
 	 * Constructor.
@@ -61,10 +66,17 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 	 */
 	public ContextEditorActionBarContributor() {
 		super();
+
+		actionUtil = new ActionUtil(this, super::selectionChanged, super::generateCreateChildActions, super::generateCreateSiblingActions);
 		validateAction = new ValidationAction();
 	}
 
 	@Override
+	protected IMenuManager createSubmenuManager() {
+		return new MenuManager(Messages.ContextEditorActionBarContributor_0, MENU_ID);
+	}
+
+	@Override
 	protected void addGlobalActions(IMenuManager menuManager) {
 		super.addGlobalActions(menuManager);
 	}
@@ -76,21 +88,17 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 
 	@Override
 	protected Collection<IAction> generateCreateChildActions(Collection<?> descriptors, ISelection selection) {
-		Collection<IAction> result = super.generateCreateChildActions(descriptors, selection);
-		if (selection instanceof IStructuredSelection) {
-			IStructuredSelection sSelection = (IStructuredSelection) selection;
-			if (sSelection.size() == 1) {
-				Object firstElement = sSelection.getFirstElement();
-				if (firstElement instanceof View) {
-					result.addAll(createChildForView(selection, (View) sSelection.getFirstElement()));
-				} else if (firstElement instanceof Section) {
-					result.addAll(createChildForSection(selection));
-				} else if (firstElement instanceof Tab) {
-					removeChildActionsForTab(result);
-				} else if (firstElement instanceof Context) {
-					removeChildActionsForContext(result);
-				}
-			}
+		Collection<IAction> result = actionUtil.createNewChildActions(descriptors, selection);
+
+		Object firstElement = ActionUtil.getElement(selection);
+		if (firstElement instanceof View) {
+			result.addAll(createChildForView(selection, (View) firstElement));
+		} else if (firstElement instanceof Section) {
+			result.addAll(createChildForSection(selection));
+		} else if (firstElement instanceof Tab) {
+			removeChildActionsForTab(result);
+		} else if (firstElement instanceof Context) {
+			removeChildActionsForContext(result);
 		}
 
 		return result;
@@ -98,7 +106,8 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 
 	@Override
 	protected Collection<IAction> generateCreateSiblingActions(Collection<?> descriptors, ISelection selection) {
-		Collection<IAction> result = super.generateCreateSiblingActions(descriptors, selection);
+		Collection<IAction> result = actionUtil.createNewSiblingActions(descriptors, selection);
+
 		if (selection instanceof IStructuredSelection) {
 			IStructuredSelection sSelection = (IStructuredSelection) selection;
 			if (sSelection.size() == 1) {
@@ -126,7 +135,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 			IAction action = iterator.next();
 			if (action instanceof CreateChildAction) {
 				CreateChildAction createChildAction = (CreateChildAction) action;
-				if (createChildAction.getText().equals("Section")) { //It's the only relevant property we have access to... //$NON-NLS-1$
+				if (createChildAction.getText().equals("Section")) { // It's the only relevant property we have access to... //$NON-NLS-1$
 					iterator.remove();
 				}
 			}
@@ -145,10 +154,8 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 			IAction action = iterator.next();
 			if (action instanceof CreateChildAction) {
 				CreateChildAction createChildAction = (CreateChildAction) action;
-				if (!ToggleDataContextAction.showDataContext) {
-					if (createChildAction.getText().equals("Data Context Root")) { //It's the only relevant property we have access to... //$NON-NLS-1$
-						iterator.remove();
-					}
+				if (createChildAction.getText().equals("Data Context Root")) { // It's the only relevant property we have access to... //$NON-NLS-1$
+					iterator.remove();
 				}
 			}
 		}
@@ -166,7 +173,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 			IAction action = iterator.next();
 			if (action instanceof CreateSiblingAction) {
 				CreateSiblingAction createSiblingAction = (CreateSiblingAction) action;
-				if (createSiblingAction.getText().equals("Data Context Root")) { //It's the only relevant property we have access to... //$NON-NLS-1$
+				if (createSiblingAction.getText().equals("Data Context Root")) { // It's the only relevant property we have access to... //$NON-NLS-1$
 					iterator.remove();
 				}
 			}
@@ -185,7 +192,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 			IAction action = iterator.next();
 			if (action instanceof CreateSiblingAction) {
 				CreateSiblingAction createSiblingAction = (CreateSiblingAction) action;
-				if (createSiblingAction.getText().equals("Section")) { //It's the only relevant property we have access to... //$NON-NLS-1$
+				if (createSiblingAction.getText().equals("Section")) { // It's the only relevant property we have access to... //$NON-NLS-1$
 					iterator.remove();
 				}
 			}
@@ -203,7 +210,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 	 *         The list of newly created {@link IAction}s
 	 */
 	protected Collection<IAction> createSiblingActionsForSection(ISelection selection, Section section) {
-		Collection<IAction> actions = new LinkedList<IAction>();
+		Collection<IAction> actions = new LinkedList<>();
 
 		// TODO : We need to retrieve the view owning the section. It is only possible with an access to the
 		// ITreeElements, which we don't have here. Find a way to retrieve it.
@@ -227,7 +234,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 	 *         The list of newly created {@link IAction}s
 	 */
 	protected Collection<IAction> createChildForView(ISelection selection, View view) {
-		Collection<IAction> actions = new LinkedList<IAction>();
+		Collection<IAction> actions = new LinkedList<>();
 		if (view.getContext() == null) {
 			return actions;
 		}
@@ -301,7 +308,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 	 *         The newly created {@link IAction}s
 	 */
 	protected Collection<IAction> createChildForSection(ISelection selection) {
-		Collection<IAction> actions = new LinkedList<IAction>();
+		Collection<IAction> actions = new LinkedList<>();
 
 		actions.add(new CreateSectionWidgetAction(selection));
 
@@ -310,11 +317,7 @@ public class ContextEditorActionBarContributor extends EcoreActionBarContributor
 
 	@Override
 	public void selectionChanged(SelectionChangedEvent event) {
-		ISelection newSelection = ActionUtil.getAdaptedSelection(event.getSelection());
-
-		SelectionChangedEvent newEvent = new SelectionChangedEvent(event.getSelectionProvider(), newSelection);
-
-		super.selectionChanged(newEvent);
+		actionUtil.selectionChanged(event);
 	}
 
 	@Override
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/UIEditor.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/UIEditor.java
index a9bf613121c..178ada406f1 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/UIEditor.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/UIEditor.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2013, 2019 CEA LIST.
+ * Copyright (c) 2010, 2021, 2019 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -12,9 +12,12 @@
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Christian W. Damus (CEA) - Factor out workspace storage for pluggable storage providers (CDO)
  *  Nicolas FAUVERGUE (CEA) nicolas.fauvergue@cea.fr - Bug 548720
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.editor;
 
+import static org.eclipse.papyrus.views.properties.toolsmiths.preferences.CustomizationEditorActionKind.getOnOpenCustomizationEditorAction;
+
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.EventObject;
@@ -82,7 +85,9 @@ import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Menu;
 import org.eclipse.swt.widgets.Tree;
+import org.eclipse.ui.IEditorInput;
 import org.eclipse.ui.IEditorPart;
+import org.eclipse.ui.IEditorSite;
 import org.eclipse.ui.IFileEditorInput;
 import org.eclipse.ui.IPerspectiveDescriptor;
 import org.eclipse.ui.IWorkbenchPage;
@@ -109,6 +114,14 @@ public class UIEditor extends EcoreEditor implements ITabbedPropertySheetPageCon
 	private TreeViewer selectionViewer;
 
 	@Override
+	public void init(IEditorSite site, IEditorInput editorInput) {
+		super.init(site, editorInput);
+
+		IWorkbenchPage page = site.getPage();
+		page.getWorkbenchWindow().getShell().getDisplay().asyncExec(() -> getOnOpenCustomizationEditorAction().perform(page));
+	}
+
+	@Override
 	public void createPages() {
 		// Creates the model from the editor input
 		//
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/ToggleDataContextAction.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/ToggleDataContextAction.java
deleted file mode 100644
index 588fe94c306..00000000000
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/ToggleDataContextAction.java
+++ /dev/null
@@ -1,50 +0,0 @@
-/*****************************************************************************
- * Copyright (c) 2011 CEA LIST.
- *
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License 2.0
- * which accompanies this distribution, and is available at
- * https://www.eclipse.org/legal/epl-2.0/
- *
- * SPDX-License-Identifier: EPL-2.0
- *
- * Contributors:
- *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
- *****************************************************************************/
-package org.eclipse.papyrus.views.properties.toolsmiths.editor.actions;
-
-import org.eclipse.core.commands.AbstractHandler;
-import org.eclipse.core.commands.ExecutionEvent;
-import org.eclipse.core.commands.ExecutionException;
-import org.eclipse.papyrus.views.properties.toolsmiths.editor.UIEditor;
-import org.eclipse.ui.IEditorPart;
-import org.eclipse.ui.PlatformUI;
-
-/**
- * An action to toggle the display of the DataContextElements in the UIEditor
- *
- * @author Camille Letavernier
- *
- */
-public class ToggleDataContextAction extends AbstractHandler {
-
-	/**
-	 * Indicates if the DataContextElements should be displayed
-	 */
-	public static boolean showDataContext = false;
-
-	@Override
-	public Object execute(ExecutionEvent event) throws ExecutionException {
-		showDataContext = !showDataContext;
-		IEditorPart editor = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage().getActiveEditor();
-		if (editor instanceof UIEditor) {
-			UIEditor uiEditor = (UIEditor) editor;
-			uiEditor.getViewer().refresh();
-		}
-
-		//		State state = event.getCommand().getState("org.eclipse.papyrus.customization.properties.displayContextState"); //$NON-NLS-1$
-		// state.setValue(showDataContext);
-		return null;
-	}
-
-}
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/ToggleDataContextState.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/ToggleDataContextState.java
deleted file mode 100644
index 3a6c413ce9d..00000000000
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/ToggleDataContextState.java
+++ /dev/null
@@ -1,21 +0,0 @@
-/*****************************************************************************
- * Copyright (c) 2011 CEA LIST.
- *
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License 2.0
- * which accompanies this distribution, and is available at
- * https://www.eclipse.org/legal/epl-2.0/
- *
- * SPDX-License-Identifier: EPL-2.0
- *
- * Contributors:
- *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
- *****************************************************************************/
-package org.eclipse.papyrus.views.properties.toolsmiths.editor.actions;
-
-import org.eclipse.core.commands.State;
-
-
-public class ToggleDataContextState extends State {
-
-}
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewAction.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewAction.java
index 3d5fc4654f4..7dc57289d4f 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewAction.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewAction.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2011 CEA LIST.
+ * Copyright (c) 2011, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,17 +10,23 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.editor.actions;
 
 import org.eclipse.core.commands.AbstractHandler;
+import org.eclipse.core.commands.Command;
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.commands.ExecutionException;
+import org.eclipse.core.commands.State;
 import org.eclipse.papyrus.views.properties.toolsmiths.Activator;
+import org.eclipse.ui.ISources;
 import org.eclipse.ui.IViewReference;
 import org.eclipse.ui.IWorkbenchPage;
+import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.PartInitException;
-import org.eclipse.ui.PlatformUI;
+import org.eclipse.ui.commands.ICommandService;
+import org.eclipse.ui.handlers.HandlerUtil;
 import org.eclipse.ui.part.ViewPart;
 
 /**
@@ -30,34 +36,22 @@ import org.eclipse.ui.part.ViewPart;
  */
 public class TogglePreviewAction extends AbstractHandler {
 
+	private static final String STATE_ID = "org.eclipse.ui.commands.toggleState"; //$NON-NLS-1$
+	private static final String COMMAND_ID = "org.eclipse.papyrus.customization.properties.TogglePreview"; //$NON-NLS-1$
+
 	@Override
 	public Object execute(ExecutionEvent event) throws ExecutionException {
-
-		// System.out.println("Toggle");
-
-		event.getCommand().getState("org.eclipse.papyrus.customization.properties.previewstate"); //$NON-NLS-1$
-
-		IWorkbenchPage activePage = PlatformUI.getWorkbench().getActiveWorkbenchWindow().getActivePage();
+		IWorkbenchPage activePage = HandlerUtil.getActiveWorkbenchWindowChecked(event).getActivePage();
 		if (activePage == null) {
 			return null;
 		}
 
-		// System.out.println("ActivePage is " + activePage);
-
-		IViewReference viewReference = null;
-
-		for (IViewReference reference : activePage.getViewReferences()) {
-			if (reference.getId().equals(Activator.PREVIEW_ID)) {
-				viewReference = reference;
-			}
-		}
+		IViewReference viewReference = activePage.findViewReference(Activator.PREVIEW_ID);
 
 		try {
 			if (viewReference == null) {
-				// System.out.println("Opening view");
 				activePage.showView(Activator.PREVIEW_ID);
 			} else {
-				// System.out.println("Closing view");
 				activePage.hideView((ViewPart) viewReference.getPart(false));
 			}
 		} catch (PartInitException ex) {
@@ -67,5 +61,26 @@ public class TogglePreviewAction extends AbstractHandler {
 		return null;
 	}
 
+	@Override
+	public void setEnabled(Object evaluationContext) {
+		super.setEnabled(evaluationContext);
+
+		IWorkbenchWindow activeWindow = (IWorkbenchWindow) HandlerUtil.getVariable(evaluationContext, ISources.ACTIVE_WORKBENCH_WINDOW_NAME);
+		IWorkbenchPage activePage = activeWindow == null ? null : activeWindow.getActivePage();
+		if (activePage == null) {
+			return;
+		}
+
+		ICommandService commandService = activeWindow.getService(ICommandService.class);
+		Command command = commandService.getCommand(COMMAND_ID);
+
+		State state = (command == null) ? null : command.getState(STATE_ID);
+		if (state == null) {
+			return;
+		}
+
+		IViewReference viewReference = activePage.findViewReference(Activator.PREVIEW_ID);
+		state.setValue(viewReference != null);
+	}
 
 }
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewState.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewState.java
deleted file mode 100644
index e370ec3c223..00000000000
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/editor/actions/TogglePreviewState.java
+++ /dev/null
@@ -1,153 +0,0 @@
-/*****************************************************************************
- * Copyright (c) 2011 CEA LIST.
- *
- * All rights reserved. This program and the accompanying materials
- * are made available under the terms of the Eclipse Public License 2.0
- * which accompanies this distribution, and is available at
- * https://www.eclipse.org/legal/epl-2.0/
- *
- * SPDX-License-Identifier: EPL-2.0
- *
- * Contributors:
- *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
- *****************************************************************************/
-package org.eclipse.papyrus.views.properties.toolsmiths.editor.actions;
-
-import org.eclipse.core.commands.State;
-import org.eclipse.papyrus.views.properties.toolsmiths.editor.preview.Preview;
-import org.eclipse.ui.IPartListener;
-import org.eclipse.ui.IWindowListener;
-import org.eclipse.ui.IWorkbenchPage;
-import org.eclipse.ui.IWorkbenchPart;
-import org.eclipse.ui.IWorkbenchWindow;
-
-/**
- * A State to determine if the Preview view is opened in the current perspective
- * The State should listen on the workbench an update itself when the perspective
- * changes, or when the preview is opened or closed
- *
- * @FIXME : the state is not correctly retrieved
- * @author Camille Letavernier
- */
-public class TogglePreviewState extends State implements IWindowListener, IPartListener {
-
-	private boolean isPreviewOpen;
-
-	public TogglePreviewState() {
-		// System.out.println("Building ToggleState");
-		//
-		// IWorkbench workbench = PlatformUI.getWorkbench();
-		//
-		// workbench.addWindowListener(this);
-		// for(IWorkbenchWindow window : workbench.getWorkbenchWindows()) {
-		// System.out.println("Listening on " + window);
-		// window.getPartService().addPartListener(this);
-		// }
-		// refreshState();
-	}
-
-	private void refreshState() {
-		// isPreviewOpen = false;
-		// System.out.println("Refresh state");
-		//
-		// IWorkbenchWindow window = PlatformUI.getWorkbench().getActiveWorkbenchWindow();
-		// if(window != null) {
-		// IWorkbenchPage page = window.getActivePage();
-		//
-		// if(page != null) {
-		// for(IViewReference reference : page.getViewReferences()) {
-		// if(reference.getId().equals(Activator.PREVIEW_ID)) {
-		// isPreviewOpen = true;
-		// break;
-		// }
-		// }
-		// }
-		// }
-		//
-		// System.out.println("IsOpen : " + isPreviewOpen);
-		//
-		// setValue(isPreviewOpen);
-	}
-
-	@Override
-	public Object getValue() {
-		return isPreviewOpen;
-	}
-
-	// IWindowListener
-
-	@Override
-	public void windowOpened(IWorkbenchWindow window) {
-		// System.out.println("Listening on " + window);
-		window.getPartService().addPartListener(this);
-		refreshState();
-	}
-
-	@Override
-	public void windowClosed(IWorkbenchWindow window) {
-		// window.removePageListener(this);
-		window.getPartService().removePartListener(this);
-	}
-
-	// IPageListener
-	//
-	// public void pageOpened(IWorkbenchPage page) {
-	// page.addPartListener(this);
-	// }
-	//
-	// public void pageClosed(IWorkbenchPage page) {
-	// page.removePartListener(this);
-	// }
-
-	// IPartListener
-
-	@Override
-	public void partOpened(IWorkbenchPart part) {
-		if (part instanceof Preview) {
-			// System.out.println("Closing preview");
-			refreshState();
-		}
-	}
-
-	@Override
-	public void partClosed(IWorkbenchPart part) {
-		if (part instanceof Preview) {
-			// System.out.println("Closing preview");
-			refreshState();
-		}
-	}
-
-	// Ignored methods
-
-	@Override
-	public void partActivated(IWorkbenchPart part) {
-		// System.out.println("Part activated");
-		// refreshState();
-	}
-
-	@Override
-	public void partBroughtToTop(IWorkbenchPart part) {
-		// Nothing
-	}
-
-	@Override
-	public void partDeactivated(IWorkbenchPart part) {
-		// System.out.println("Part activated");
-		// refreshState();
-	}
-
-	@Override
-	public void windowActivated(IWorkbenchWindow window) {
-		// Nothing
-	}
-
-	@Override
-	public void windowDeactivated(IWorkbenchWindow window) {
-		// Nothing
-	}
-
-	public void pageActivated(IWorkbenchPage page) {
-		// Nothing
-	}
-
-}
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/Messages.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/Messages.java
index ce4247120f6..c27f5baf4d4 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/Messages.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/Messages.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010, 2013 CEA LIST.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -11,6 +11,7 @@
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
  *  Christian W. Damus (CEA) - Factor out workspace storage for pluggable storage providers (CDO)
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.messages;
 
@@ -21,6 +22,8 @@ public class Messages extends NLS {
 
 	private static final String BUNDLE_NAME = "org.eclipse.papyrus.views.properties.toolsmiths.messages.messages"; //$NON-NLS-1$
 
+	public static String ContextEditorActionBarContributor_0;
+
 	public static String CopyContextAction_Copying;
 
 	public static String CopyContextAction_InitializingTheCopyOf;
@@ -73,6 +76,18 @@ public class Messages extends NLS {
 
 	public static String CustomizationDialog_selectContextToEdit;
 
+	public static String CustomizationEditorActionKind_0;
+
+	public static String CustomizationEditorActionKind_1;
+
+	public static String CustomizationEditorActionKind_2;
+
+	public static String CustomizationEditorActionKind_3;
+
+	public static String CustomizationEditorActionKind_4;
+
+	public static String CustomizationPreferencePage_0;
+
 	public static String CustomizationPreferencePage_AskForConfirmation;
 
 	public static String CustomizationPreferencePage_OpenCustomizationPerspective;
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/messages.properties b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/messages.properties
index bdc5b473bf5..46e961536aa 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/messages.properties
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/messages/messages.properties
@@ -1,5 +1,5 @@
 #############################################################################
-# Copyright (c) 2011, 2013 CEA LIST.
+# Copyright (c) 2011, 2021 CEA LIST, Christian W. Damus, and others.
 # 
 # All rights reserved. This program and the accompanying materials
 # are made available under the terms of the Eclipse Public License 2.0
@@ -11,7 +11,9 @@
 # Contributors:
 #   CEA LIST - Initial API and implementation
 #   Christian W. Damus (CEA) - Factor out workspace storage for pluggable storage providers (CDO)
+#   Christian W. Damus - bug 573987
 #############################################################################
+ContextEditorActionBarContributor_0=Context Editor
 CopyContextAction_Copying=Copying 
 CopyContextAction_InitializingTheCopyOf=Initializing the copy of 
 CopyContextAction_ThisMayTakeSomeTime=. This may take some time
@@ -38,6 +40,12 @@ CustomizationDialog_enterConfigurationName=Enter the new configuration name
 CustomizationDialog_plugin=\ (Read-only)
 CustomizationDialog_removeSelectedContext=Removes the selected Context. This option is only available for writeable Contexts
 CustomizationDialog_selectContextToEdit=Select a context to edit. Read-only contexts should be copied before they can be edited.
+CustomizationEditorActionKind_0=Customization Perspective
+CustomizationEditorActionKind_1=Customization Preview
+CustomizationEditorActionKind_2=Remember my decision
+CustomizationEditorActionKind_3=Customization Editor
+CustomizationEditorActionKind_4=The customization editor is usually associated with the customization perspective or preview view. What would you like to do?
+CustomizationPreferencePage_0=On opening the customization editor
 CustomizationPreferencePage_AskForConfirmation=Ask for confirmation
 CustomizationPreferencePage_OpenCustomizationPerspective=Open customization perspective
 CustomizationPreferencePage_PropertyViewCustomizationPreferences=Property view customization preferences
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationEditorActionKind.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationEditorActionKind.java
new file mode 100644
index 00000000000..55f264b232b
--- /dev/null
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationEditorActionKind.java
@@ -0,0 +1,156 @@
+/*****************************************************************************
+ * Copyright (c) 2021 Christian W. Damus, CEA LIST, and others.
+ *
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *   Christian W. Damus - Initial API and implementation
+ *
+ *****************************************************************************/
+
+package org.eclipse.papyrus.views.properties.toolsmiths.preferences;
+
+import static java.util.function.Predicate.not;
+import static org.eclipse.papyrus.views.properties.toolsmiths.preferences.CustomizationPreferencePage.ON_OPEN_CUSTOMIZATION_EDITOR;
+
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.Optional;
+
+import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.jface.dialogs.MessageDialogWithToggle;
+import org.eclipse.jface.util.Policy;
+import org.eclipse.papyrus.views.properties.toolsmiths.Activator;
+import org.eclipse.papyrus.views.properties.toolsmiths.messages.Messages;
+import org.eclipse.ui.IPerspectiveDescriptor;
+import org.eclipse.ui.IWorkbenchPage;
+import org.eclipse.ui.PartInitException;
+import org.eclipse.ui.WorkbenchException;
+
+/**
+ * Enumeration of action preferences for the opening of the customization editor.
+ */
+public enum CustomizationEditorActionKind {
+	/** An "action" that simply does nothing when the customization editor is opened. */
+	NOTHING("Do nothing"), //$NON-NLS-1$
+	/** An action that switches the editor's window's perspective to the <em>Customization Perspective</em>. */
+	PERSPECTIVE("Open the customization perspective"), //$NON-NLS-1$
+	/** An action that shows the <em>Customization Preview</em> view in the editor's workbench page. */
+	PREVIEW("Open the customization preview view"), //$NON-NLS-1$
+	/**
+	 * An action that prompts the user which action to take, with option to remember the decision in the
+	 * preferences, and then delegates to the selected action.
+	 */
+	PROMPT("Ask what to do"); //$NON-NLS-1$
+
+	private final String label;
+
+	CustomizationEditorActionKind(String label) {
+		this.label = label;
+	}
+
+	/**
+	 * Obtain a label to present in the user interface, in the preference selection
+	 * and dialog buttons.
+	 *
+	 * @return a translatable label
+	 */
+	public String getLabel() {
+		return label;
+	}
+
+	/**
+	 * Perform the action that I represent. Note that all actions are no-ops if the current perspective
+	 * of the given workbench page is the <em>Customization Perspective</em>, as that is the ideal scenario.
+	 * Most especially, in that case the user would not be prompted for an action if the current preference
+	 * is to ask each time.
+	 *
+	 * @param workbenchPage
+	 *            the workbench page in which the customization editor is opened
+	 */
+	public void perform(IWorkbenchPage workbenchPage) {
+		IPerspectiveDescriptor perspective = workbenchPage.getPerspective();
+		if (perspective != null && Activator.CUSTOMIZATION_PERSPECTIVE_ID.equals(perspective.getId())) {
+			// Nothing to do
+			return;
+		}
+
+		switch (this) {
+		case PERSPECTIVE:
+			try {
+				workbenchPage.getWorkbenchWindow().getWorkbench().showPerspective(Activator.CUSTOMIZATION_PERSPECTIVE_ID, workbenchPage.getWorkbenchWindow());
+			} catch (WorkbenchException e) {
+				Policy.getStatusHandler().show(e.getStatus(), Messages.CustomizationEditorActionKind_0);
+			}
+			break;
+		case PREVIEW:
+			try {
+				// There's no harm in showing a view that is already present. And it would be brought
+				// to the front of its stack
+				workbenchPage.showView(Activator.PREVIEW_ID);
+			} catch (PartInitException e) {
+				Policy.getStatusHandler().show(e.getStatus(), Messages.CustomizationEditorActionKind_1);
+			}
+			break;
+		case PROMPT:
+			prompt(workbenchPage);
+			break;
+		default:
+			// Pass
+			break;
+		}
+	}
+
+	/**
+	 * Query the action to perform on opening the customization editor.
+	 *
+	 * @return the customization editor action kind
+	 */
+	public static CustomizationEditorActionKind getOnOpenCustomizationEditorAction() {
+		String pref = Optional.ofNullable(Activator.getDefault().getPreferenceStore().getString(ON_OPEN_CUSTOMIZATION_EDITOR))
+				.filter(not(String::isBlank)).orElse(getDefault().name());
+		return CustomizationEditorActionKind.valueOf(pref);
+	}
+
+	/**
+	 * Query the default value of the customization editor action preference.
+	 *
+	 * @return the default preference value, which is to {@linkplain #PROMPT prompt the user}
+	 */
+	public static CustomizationEditorActionKind getDefault() {
+		return PROMPT;
+	}
+
+	private static void prompt(IWorkbenchPage workbenchPage) {
+		String toggleMessage = Messages.CustomizationEditorActionKind_2;
+		LinkedHashMap<String, Integer> buttons = new LinkedHashMap<>();
+		EnumSet.complementOf(EnumSet.of(PROMPT)).forEach(v -> buttons.put(v.getLabel(), v.toButtonCode()));
+
+		MessageDialogWithToggle dialog = new MessageDialogWithToggle(workbenchPage.getWorkbenchWindow().getShell(),
+				Messages.CustomizationEditorActionKind_3, null, Messages.CustomizationEditorActionKind_4,
+				MessageDialog.QUESTION, buttons, PREVIEW.ordinal(),
+				toggleMessage, false);
+		CustomizationEditorActionKind.forButtonCode(dialog.open()).ifPresent(result -> {
+			// The result cannot be "prompt"
+			result.perform(workbenchPage);
+			if (dialog.getToggleState()) {
+				Activator.getDefault().getPreferenceStore().setValue(ON_OPEN_CUSTOMIZATION_EDITOR, result.name());
+			}
+		});
+	}
+
+	int toButtonCode() {
+		// Avoid the stock OK and Cancel values
+		return ordinal() + 2;
+	}
+
+	static Optional<CustomizationEditorActionKind> forButtonCode(int code) {
+		return code < 2 ? Optional.empty() : Optional.of(values()[code - 2]);
+	}
+
+}
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencePage.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencePage.java
index 10cd711442a..de0a90c6790 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencePage.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencePage.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010 CEA LIST.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,10 +10,14 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.preferences;
 
+import java.util.stream.Stream;
+
 import org.eclipse.jface.preference.BooleanFieldEditor;
+import org.eclipse.jface.preference.ComboFieldEditor;
 import org.eclipse.jface.preference.FieldEditorPreferencePage;
 import org.eclipse.jface.resource.ImageDescriptor;
 import org.eclipse.papyrus.views.properties.toolsmiths.Activator;
@@ -38,6 +42,8 @@ public class CustomizationPreferencePage extends FieldEditorPreferencePage imple
 	 */
 	public static final String ASK_FOR_CONFIRMATION = "askForConfirmation"; //$NON-NLS-1$
 
+	public static final String ON_OPEN_CUSTOMIZATION_EDITOR = "onOpenCustomizationEditor"; //$NON-NLS-1$
+
 	/**
 	 *
 	 * Constructor.
@@ -89,6 +95,11 @@ public class CustomizationPreferencePage extends FieldEditorPreferencePage imple
 	protected void createFieldEditors() {
 		addField(new BooleanFieldEditor(OPEN_CUSTOMIZATION_PERSPECTIVE, Messages.CustomizationPreferencePage_OpenCustomizationPerspective, getFieldEditorParent()));
 		addField(new BooleanFieldEditor(ASK_FOR_CONFIRMATION, Messages.CustomizationPreferencePage_AskForConfirmation, getFieldEditorParent()));
+
+		String[][] onOpenCustomizationEditor = Stream.of(CustomizationEditorActionKind.values())
+				.map(v -> new String[] { v.getLabel(), v.name() })
+				.toArray(String[][]::new);
+		addField(new ComboFieldEditor(ON_OPEN_CUSTOMIZATION_EDITOR, Messages.CustomizationPreferencePage_0, onOpenCustomizationEditor, getFieldEditorParent()));
 	}
 
 	/**
@@ -109,4 +120,5 @@ public class CustomizationPreferencePage extends FieldEditorPreferencePage imple
 	public static boolean askForConfirmation() {
 		return Activator.getDefault().getPreferenceStore().getBoolean(ASK_FOR_CONFIRMATION);
 	}
+
 }
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencesInitializer.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencesInitializer.java
index c56f0a73eb0..f0c7be8894a 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencesInitializer.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/preferences/CustomizationPreferencesInitializer.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2011 CEA LIST.
+ * Copyright (c) 2011, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,12 +10,12 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.preferences;
 
 import org.eclipse.core.runtime.preferences.AbstractPreferenceInitializer;
 import org.eclipse.jface.preference.IPreferenceStore;
-import org.eclipse.papyrus.views.properties.toolsmiths.preferences.CustomizationPreferencePage;
 import org.eclipse.papyrus.views.properties.toolsmiths.Activator;
 
 /**
@@ -30,6 +30,7 @@ public class CustomizationPreferencesInitializer extends AbstractPreferenceIniti
 		IPreferenceStore store = Activator.getDefault().getPreferenceStore();
 		store.setDefault(CustomizationPreferencePage.OPEN_CUSTOMIZATION_PERSPECTIVE, true);
 		store.setDefault(CustomizationPreferencePage.ASK_FOR_CONFIRMATION, true);
+		store.setDefault(CustomizationPreferencePage.OPEN_CUSTOMIZATION_PERSPECTIVE, CustomizationEditorActionKind.getDefault().name());
 	}
 
 }
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/GetVisibleFeaturesQuery.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/GetVisibleFeaturesQuery.java
index 4599ca629f9..2f35923e17e 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/GetVisibleFeaturesQuery.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/GetVisibleFeaturesQuery.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2016 CEA LIST and others.
+ * Copyright (c) 2016, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,6 +10,7 @@
  *
  * Contributors:
  *   CEA LIST - Initial API and implementation
+ *   Christian W. Damus - bug 573987
  *
  *****************************************************************************/
 
@@ -35,7 +36,6 @@ import org.eclipse.papyrus.infra.properties.contexts.Context;
 import org.eclipse.papyrus.infra.properties.contexts.ContextsPackage;
 import org.eclipse.papyrus.infra.properties.contexts.util.ContextsSwitch;
 import org.eclipse.papyrus.infra.properties.ui.UiPackage;
-import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.ToggleDataContextAction;
 
 /**
  * @author Camille Letavernier
@@ -104,9 +104,7 @@ public class GetVisibleFeaturesQuery implements IJavaQuery2<EObject, List<ERefer
 
 	protected Predicate<EReference> filterContextReferences(Context object) {
 		return ref -> {
-			if (ref == ContextsPackage.Literals.CONTEXT__DATA_CONTEXTS) { // Show DataContexts only if the corresponding action is enabled
-				return ToggleDataContextAction.showDataContext;
-			} else if (ref == ContextsPackage.Literals.CONTEXT__PROTOTYPE) { // Show the Prototype reference only if it is set
+			if (ref == ContextsPackage.Literals.CONTEXT__PROTOTYPE) { // Show the Prototype reference only if it is set
 				return object.getPrototype() != null;
 			}
 			return true;
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/ShowContextQuery.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/ShowContextQuery.java
index b3029b40850..0ea0a305520 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/ShowContextQuery.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/query/ShowContextQuery.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2011 CEA LIST.
+ * Copyright (c) 2011, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,6 +10,7 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.query;
 
@@ -18,19 +19,22 @@ import org.eclipse.papyrus.emf.facet.efacet.core.exception.DerivedTypedElementEx
 import org.eclipse.papyrus.emf.facet.query.java.core.IJavaQuery2;
 import org.eclipse.papyrus.emf.facet.query.java.core.IParameterValueList2;
 import org.eclipse.papyrus.infra.properties.contexts.Context;
-import org.eclipse.papyrus.views.properties.toolsmiths.editor.actions.ToggleDataContextAction;
+import org.eclipse.papyrus.infra.properties.contexts.DataContextElement;
 
 /**
- * A Query to test if the DataContextElements should be displayed in the UIEditor
+ * A Query to test if the {@link DataContextElement}s should be displayed in the {@code UIEditor}.
  *
  * @author Camille Letavernier
+ *
+ * @deprecated Since the 3.2 release of the bundle, contexts are always shown in the editor.
  */
+@Deprecated(since = "3.2")
 public class ShowContextQuery implements IJavaQuery2<Context, Boolean> {
 
 
 	@Override
 	public Boolean evaluate(Context source, IParameterValueList2 parameterValues, IFacetManager facetManager) throws DerivedTypedElementException {
-		Boolean result = ToggleDataContextAction.showDataContext;
+		Boolean result = true;
 		return result;
 	}
 
diff --git a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/util/ActionUtil.java b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/util/ActionUtil.java
index 8afdd39c7e0..f1a9f0b2071 100644
--- a/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/util/ActionUtil.java
+++ b/plugins/views/properties/org.eclipse.papyrus.views.properties.toolsmiths/src/org/eclipse/papyrus/views/properties/toolsmiths/util/ActionUtil.java
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * Copyright (c) 2010 CEA LIST.
+ * Copyright (c) 2010, 2021 CEA LIST, Christian W. Damus, and others.
  *
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -10,27 +10,80 @@
  *
  * Contributors:
  *  Camille Letavernier (CEA LIST) camille.letavernier@cea.fr - Initial API and implementation
+ *  Christian W. Damus - bug 573987
  *****************************************************************************/
 package org.eclipse.papyrus.views.properties.toolsmiths.util;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.function.BiFunction;
+import java.util.function.Consumer;
 
 import org.eclipse.emf.ecore.EObject;
+import org.eclipse.emf.ecore.EStructuralFeature;
+import org.eclipse.emf.edit.command.CommandParameter;
+import org.eclipse.emf.edit.domain.EditingDomain;
+import org.eclipse.emf.edit.domain.IEditingDomainProvider;
+import org.eclipse.emf.edit.ui.action.EditingDomainActionBarContributor;
+import org.eclipse.jface.action.IAction;
 import org.eclipse.jface.viewers.ISelection;
+import org.eclipse.jface.viewers.ISelectionChangedListener;
+import org.eclipse.jface.viewers.IStructuredSelection;
+import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
+import org.eclipse.papyrus.emf.facet.custom.metamodel.v0_2_0.internal.treeproxy.EAttributeTreeElement;
+import org.eclipse.papyrus.emf.facet.custom.metamodel.v0_2_0.internal.treeproxy.EObjectTreeElement;
+import org.eclipse.papyrus.emf.facet.custom.metamodel.v0_2_0.internal.treeproxy.EReferenceTreeElement;
+import org.eclipse.papyrus.emf.facet.custom.metamodel.v0_2_0.internal.treeproxy.EStructuralFeatureTreeElement;
+import org.eclipse.papyrus.emf.facet.custom.metamodel.v0_2_0.internal.treeproxy.TreeElement;
 import org.eclipse.papyrus.infra.emf.utils.EMFHelper;
 
 /**
- * Utility class for Actions
+ * Utility class for Actions.
  *
  * @author Camille Letavernier
  *
  */
 public class ActionUtil {
 
+	private final EditingDomainActionBarContributor contributor;
+	private final Consumer<? super SelectionChangedEvent> selectionChangedHandler;
+	private final BiFunction<? super Collection<?>, ? super ISelection, ? extends Collection<IAction>> newChildActionsGenerator;
+	private final BiFunction<? super Collection<?>, ? super ISelection, ? extends Collection<IAction>> newSiblingActionsGenerator;
+
+	private ISelection originalSelection;
+
+	/**
+	 * Initialize a utility instance for use in an action bar {@code contributor}.
+	 *
+	 * @param contributor
+	 *            the action-bar contributor that owns me
+	 * @param selectionChangedHandler
+	 *            the basic selection-change handler of the {@code contributor}. This should usually be its EMF-generated
+	 *            implementation of {@link ISelectionChangedListener#selectionChanged(SelectionChangedEvent)}
+	 * @param newChildActionsGenerator
+	 *            the basic new child actions creation method of the {@code contributor}. This should usually be its
+	 *            EMF-generated implementation of {@code generateCreateChildActions(...)}
+	 * @param newSiblingActionsGenerator
+	 *            the basic new sibling actions creation method of the {@code contributor}. This should usually be its
+	 *            EMF-generated implementation of {@code generateCreateSiblingActions(...)}
+	 */
+	public ActionUtil(EditingDomainActionBarContributor contributor,
+			Consumer<? super SelectionChangedEvent> selectionChangedHandler,
+			BiFunction<? super Collection<?>, ? super ISelection, ? extends Collection<IAction>> newChildActionsGenerator,
+			BiFunction<? super Collection<?>, ? super ISelection, ? extends Collection<IAction>> newSiblingActionsGenerator) {
+
+		super();
+
+		this.contributor = contributor;
+		this.selectionChangedHandler = selectionChangedHandler;
+		this.newChildActionsGenerator = newChildActionsGenerator;
+		this.newSiblingActionsGenerator = newSiblingActionsGenerator;
+	}
+
 	/**
 	 * EMF can only handle collections of EObjects. However, as the
 	 * customization plugin relies a lot on EMF Facet, we often have to handle
@@ -45,7 +98,7 @@ public class ActionUtil {
 	 *         The adapted selection
 	 */
 	public static Collection<Object> getAdaptedSelection(Collection<? extends Object> selection) {
-		Collection<Object> newSelection = new LinkedList<Object>();
+		Collection<Object> newSelection = new LinkedList<>();
 		for (Object o : selection) {
 			EObject semantic = EMFHelper.getEObject(o);
 			newSelection.add(semantic == null ? o : semantic);
@@ -69,7 +122,7 @@ public class ActionUtil {
 	public static ISelection getAdaptedSelection(ISelection sourceSelection) {
 		if (sourceSelection instanceof StructuredSelection) {
 			StructuredSelection currentSelection = (StructuredSelection) sourceSelection;
-			List<Object> newSelection = new LinkedList<Object>();
+			List<Object> newSelection = new LinkedList<>();
 
 			Iterator<?> it = currentSelection.iterator();
 			while (it.hasNext()) {
@@ -84,4 +137,193 @@ public class ActionUtil {
 			return sourceSelection;
 		}
 	}
+
+	/**
+	 * Get the only element of a {@code selection} if it is a structured selection containing exactly one element.
+	 *
+	 * @param selection
+	 *            a selection
+	 * @return its one and only (structured) element
+	 */
+	public static Object getElement(ISelection selection) {
+		Object result = null;
+
+		if (selection instanceof IStructuredSelection) {
+			IStructuredSelection structured = (IStructuredSelection) selection;
+			if (structured.size() == 1) {
+				result = structured.getFirstElement();
+			}
+		}
+
+		return result;
+	}
+
+	/**
+	 * If the {@code selection} contains an <em>EMF Facet</em> tree node, get the object from it
+	 * that either the node represents or that owns it if the node is a feature node.
+	 *
+	 * @param selection
+	 *            a selection
+	 * @return the EMF object that it represents, or {@code null}
+	 *         if the selection is just a regular EMF object or something else
+	 */
+	public static EObject unwrapTreeNode(ISelection selection) {
+		EObject result = null;
+		Object firstElement = getElement(selection);
+		if (firstElement instanceof TreeElement) {
+			result = unwrapTreeNode((TreeElement) firstElement);
+		}
+		return result;
+	}
+
+	private static EObject unwrapTreeNode(TreeElement treeElement) {
+		EObject result = null;
+
+		if (treeElement instanceof EObjectTreeElement) {
+			result = ((EObjectTreeElement) treeElement).getEObject();
+		} else if (treeElement instanceof EStructuralFeatureTreeElement) {
+			EStructuralFeatureTreeElement featureElement = (EStructuralFeatureTreeElement) treeElement;
+			if (featureElement.getParent() != null) {
+				result = unwrapTreeNode(featureElement.getParent());
+			}
+		}
+
+		return result;
+	}
+
+	/**
+	 * If the {@code selection} contains an <em>EMF Facet</em> feature node, get the feature from it.
+	 *
+	 * @param selection
+	 *            a selection
+	 * @return the EMF structural feature that it represents, or {@code null}
+	 *         if the selection is just a regular EMF object or something else
+	 */
+	public static EStructuralFeature unwrapTreeFeature(ISelection selection) {
+		EStructuralFeature result = null;
+		Object firstElement = getElement(selection);
+		if (firstElement instanceof EStructuralFeatureTreeElement) {
+			result = unwrapTreeFeature((EStructuralFeatureTreeElement) firstElement);
+		}
+		return result;
+	}
+
+	private static EStructuralFeature unwrapTreeFeature(EStructuralFeatureTreeElement treeElement) {
+		EStructuralFeature result = null;
+
+		if (treeElement instanceof EAttributeTreeElement) {
+			result = ((EAttributeTreeElement) treeElement).getEAttribute();
+		} else if (treeElement instanceof EReferenceTreeElement) {
+			result = ((EReferenceTreeElement) treeElement).getEReference();
+		}
+
+		return result;
+	}
+
+	/**
+	 * If the {@code selection} contains an <em>EMF Facet</em> feature node, get the object that
+	 * owns the feature (from this node's parent).
+	 *
+	 * @param selection
+	 *            a selection
+	 * @return the EMF object that it owns the feature that the node represents, or {@code null}
+	 *         if the selection is just a regular EMF object or something else
+	 */
+	public static EStructuralFeature unwrapTreeParentFeature(ISelection selection) {
+		EStructuralFeature result = null;
+		Object firstElement = getElement(selection);
+		if (firstElement instanceof EObjectTreeElement) {
+			EObjectTreeElement object = (EObjectTreeElement) firstElement;
+			if (object.getParent() instanceof EStructuralFeatureTreeElement) {
+				result = unwrapTreeFeature((EStructuralFeatureTreeElement) object.getParent());
+			}
+		}
+		return result;
+	}
+
+	/**
+	 * Handle the selection change on behalf of the owning action bar contributor.
+	 *
+	 * @param event
+	 *            the selection change event received by the action bar contributor
+	 */
+	public void selectionChanged(SelectionChangedEvent event) {
+		originalSelection = event.getSelection();
+
+		try {
+			ISelection newSelection = ActionUtil.getAdaptedSelection(event.getSelection());
+
+			SelectionChangedEvent newEvent = new SelectionChangedEvent(event.getSelectionProvider(), newSelection);
+
+			selectionChangedHandler.accept(newEvent);
+		} finally {
+			originalSelection = null;
+		}
+
+	}
+
+	/**
+	 * Create new child actions on behalf of the owning action bar contributor.
+	 *
+	 * @param descriptors
+	 *            the new-child descriptors gathered by the base EMF contributor framework
+	 * @param the
+	 *            selection forward by the EMF contributor framework (which was replaced by this utility)
+	 * @return the actions that the contributor should return to the EMF editor
+	 */
+	public Collection<IAction> createNewChildActions(Collection<?> descriptors, ISelection selection) {
+		Collection<IAction> result;
+		EObject unwrappedTreeObject = unwrapTreeNode(originalSelection);
+		EStructuralFeature unwrappedTreeFeature = unwrapTreeFeature(originalSelection);
+
+		if (unwrappedTreeObject != null && unwrappedTreeFeature != null) {
+			descriptors = getEditingDomain().getNewChildDescriptors(unwrappedTreeObject, null);
+			descriptors.removeIf(d -> !(d instanceof CommandParameter) || ((CommandParameter) d).getEStructuralFeature() != unwrappedTreeFeature);
+			result = newChildActionsGenerator.apply(descriptors, new StructuredSelection(unwrappedTreeObject));
+		} else {
+			result = newChildActionsGenerator.apply(descriptors, selection);
+		}
+
+		return result;
+	}
+
+	/**
+	 * Create new sibling actions on behalf of the owning action bar contributor.
+	 *
+	 * @param descriptors
+	 *            the new-sibling descriptors gathered by the base EMF contributor framework
+	 * @param the
+	 *            selection forward by the EMF contributor framework (which was replaced by this utility)
+	 * @return the actions that the contributor should return to the EMF editor
+	 */
+	public Collection<IAction> createNewSiblingActions(Collection<?> descriptors, ISelection selection) {
+		Collection<IAction> result;
+		EObject unwrappedTreeObject = unwrapTreeNode(originalSelection);
+		EStructuralFeature unwrappedTreeFeature = unwrapTreeFeature(originalSelection);
+		EStructuralFeature unwrappedTreeParentFeature = unwrapTreeParentFeature(originalSelection);
+
+		if (unwrappedTreeObject != null && unwrappedTreeFeature != null) {
+			descriptors = getEditingDomain().getNewChildDescriptors(null, unwrappedTreeObject);
+			descriptors.removeIf(d -> !(d instanceof CommandParameter) || ((CommandParameter) d).getEStructuralFeature() != unwrappedTreeFeature);
+			result = newSiblingActionsGenerator.apply(descriptors, new StructuredSelection(unwrappedTreeObject));
+		} else if (unwrappedTreeObject != null && unwrappedTreeParentFeature != null) {
+			descriptors = new ArrayList<>(descriptors);
+			descriptors.removeIf(d -> !(d instanceof CommandParameter) || ((CommandParameter) d).getEStructuralFeature() != unwrappedTreeParentFeature);
+			result = newSiblingActionsGenerator.apply(descriptors, new StructuredSelection(unwrappedTreeObject));
+		} else {
+			result = newSiblingActionsGenerator.apply(descriptors, selection);
+		}
+
+		return result;
+	}
+
+	/**
+	 * Get the editor's editing domain from the contributor that owns me.
+	 *
+	 * @return the editing domain
+	 */
+	protected EditingDomain getEditingDomain() {
+		return ((IEditingDomainProvider) contributor.getActiveEditor()).getEditingDomain();
+	}
+
 }