[521701] Update doc of SelectionWizard and PaneBasedSelectionWizard

* The main add is to precise that _Root Expression_ and _Children
Expression_ are necessary if tree is ticked and provides elements that
must be included in _Candidates Expression_ elements.

Bug 521701
Change-Id: I976e38d7552dbe448478425799260bc1a18f5739
Signed-off-by: Laurent Fasani <laurent.fasani@obeo.fr>

9 files changed, 448 insertions, 389 deletions

diff --git a/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.html b/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.html
index c97b9e6230..f2786d9de4 100644
--- a/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.html
+++ b/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.html
@@ -1526,8 +1526,13 @@
 		</p>
 		<p>The 
 			<em>Candidates Expression</em> should return a list of elements from which the user can select the variable&#8217;s value. By default these candidates are presented as a list. You can also enable the 
-			<em>Tree</em> mode, and specify a 
-			<em>Children Expression</em>, which will be evaluated recursively on each candidate to build a tree of possible values. Finally, you can set the 
+			<em>Tree</em> mode to display elements as a tree. In that case, you must specify a 
+			<em>Root Expression</em> that will provide elements to be displayed as first level of the tree item in the dialog and a 
+			<em>Children Expression</em>, which will be evaluated recursively on each candidate, from the root elements, to build a tree of possible values. Note that 
+			<em>Root Expression</em> and 
+			<em>Children Expression</em> provides elements that must be included in 
+			<em>Candidates Expression</em> elements.
+			<br/>Finally, you can set the 
 			<em>Multiple</em> flag to allow users to select several of the candidates instead of a single one.
 		</p>
 		<p><div style="display: none">
diff --git a/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.textile b/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.textile
index 6f0165e491..fa5ba2e4f0 100644
--- a/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.textile
+++ b/plugins/org.eclipse.sirius.doc/doc/specifier/diagrams/Diagrams.textile
@@ -599,7 +599,8 @@ When the tool is selected, the user must first select a diagram element as the t
 
 The _Window Title_, _Icon Path_, _Windows Image Path_ and _Message_ can be used to customize the look of the selection window.
 
-The _Candidates Expression_ should return a list of elements from which the user can select the variable's value. By default these candidates are presented as a list. You can also enable the _Tree_ mode, and specify a _Children Expression_, which will be evaluated recursively on each candidate to build a tree of possible values. Finally, you can set the _Multiple_ flag to allow users to select several of the candidates instead of a single one.
+The _Candidates Expression_ should return a list of elements from which the user can select the variable's value. By default these candidates are presented as a list. You can also enable the _Tree_ mode to display elements as a tree. In that case, you must specify a _Root Expression_ that will provide elements to be displayed as first level of the tree item in the dialog and a _Children Expression_, which will be evaluated recursively on each candidate, from the root elements, to build a tree of possible values. Note that _Root Expression_ and _Children Expression_ provides elements that must be included in _Candidates Expression_ elements.
+Finally, you can set the _Multiple_ flag to allow users to select several of the candidates instead of a single one.
 
 <div style="display: none">
 *TODO* What is the context where the tool's body is executed if several elements are selected?
diff --git a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionChildrenExpressionPropertySection.java b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionChildrenExpressionPropertySection.java
index fcfe05116a..849a5e8dac 100644
--- a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionChildrenExpressionPropertySection.java
+++ b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionChildrenExpressionPropertySection.java
@@ -1,11 +1,12 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2013 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2017 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
+ * 
  * Contributors:
- *    Obeo - initial API and implementation
+ *    Obeo - initial API and implementation

  *******************************************************************************/
 package org.eclipse.sirius.editor.properties.sections.description.selectiondescription;
 
@@ -34,91 +35,91 @@ import org.eclipse.ui.views.properties.tabbed.TabbedPropertySheetPage;
  * A section for the childrenExpression property of a SelectionDescription object.
  */
 public class SelectionDescriptionChildrenExpressionPropertySection extends AbstractTextWithButtonPropertySection implements ContentProposalClient {
-
-    /** Help control of the section. */
-    protected CLabel help;
-
-    /**
-     * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
-     */
-    public void refresh() {
-        super.refresh();
-
-        final String tooltip = getToolTipText();
-        if (tooltip != null && help != null) {
-            help.setToolTipText(getToolTipText());
-        }
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
-     */
-    protected String getDefaultLabelText() {
-        return "ChildrenExpression"; //$NON-NLS-1$
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
-     */
-    protected String getLabelText() {
-        String labelText;
-        labelText = super.getLabelText() + ":"; //$NON-NLS-1$
-        // Start of user code get label text
-
-        // End of user code get label text
-        return labelText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
-     */
-    public EAttribute getFeature() {
-        return DescriptionPackage.eINSTANCE.getSelectionDescription_ChildrenExpression();
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
-     */
-    protected Object getFeatureValue(String newText) {
-        return newText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
-     */
-    protected boolean isEqual(String newText) {
-        return getFeatureAsText().equals(newText);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
-        super.createControls(parent, tabbedPropertySheetPage);
-        /*
-         * We set the color as it's a InterpretedExpression
-         */
-        text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
-
-        text.setToolTipText(getToolTipText());
-
-        help = getWidgetFactory().createCLabel(composite, "");
-        FormData data = new FormData();
+	
+	/** Help control of the section. */
+	protected CLabel help;
+	
+	/**
+	 * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
+	 */
+	public void refresh() {
+		super.refresh();
+
+		final String tooltip = getToolTipText();
+		if (tooltip != null && help != null) {
+			help.setToolTipText(getToolTipText());
+		}
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
+	 */
+	protected String getDefaultLabelText() {
+	    return "ChildrenExpression"; //$NON-NLS-1$
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
+	 */
+	protected String getLabelText() {
+		String labelText;
+		labelText = super.getLabelText() + ":"; //$NON-NLS-1$
+		// Start of user code get label text
+
+	    // End of user code get label text
+	    return labelText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
+	 */
+	public EAttribute getFeature() {
+		return DescriptionPackage.eINSTANCE.getSelectionDescription_ChildrenExpression();
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
+	 */
+	protected Object getFeatureValue(String newText) {
+		return newText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
+	 */
+	protected boolean isEqual(String newText) {
+		return getFeatureAsText().equals(newText);
+	}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
+	    super.createControls(parent, tabbedPropertySheetPage);
+	    /*
+	     * We set the color as it's a InterpretedExpression
+	     */
+	    text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
+	    
+	    text.setToolTipText(getToolTipText());
+	    	    
+	    help = getWidgetFactory().createCLabel(composite,"");
+	    FormData data = new FormData();
         data.top = new FormAttachment(text, 0, SWT.TOP);
-        data.left = new FormAttachment(nameLabel);
+        data.left = new FormAttachment(nameLabel);     
         help.setLayoutData(data);
         help.setImage(getHelpIcon());
-        help.setToolTipText(getToolTipText());
-
-        TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
-
-        // Start of user code create controls
+        help.setToolTipText(getToolTipText());	    
+	    
+         TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
+	    
+	    // Start of user code create controls
 
-        // End of user code create controls
+	    // End of user code create controls
+	    
+	}
 
-    }
-
-    @Override
+	@Override
     protected SelectionListener createButtonListener() {
         return new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
@@ -129,15 +130,15 @@ public class SelectionDescriptionChildrenExpressionPropertySection extends Abstr
             }
         };
     }
-
-    /**
-     * {@inheritDoc}
-     */
-    protected String getPropertyDescription() {
-        return "";
-    }
-
-    // Start of user code user operations
-
-    // End of user code user operations
-}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	protected String getPropertyDescription() {
+		return "Required if Tree is ticked\nThis expression will return the children of a candidate element and will be evaluated recursively on each candidate from the root elements\nThese elements must also be in the list returned by Candidates Expression";
+	}
+	
+	// Start of user code user operations
+
+	// End of user code user operations
+}
\ No newline at end of file
diff --git a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionRootExpressionPropertySection.java b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionRootExpressionPropertySection.java
index c646488596..81db387204 100644
--- a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionRootExpressionPropertySection.java
+++ b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionRootExpressionPropertySection.java
@@ -1,11 +1,12 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2013 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2017 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
+ * 
  * Contributors:
- *    Obeo - initial API and implementation
+ *    Obeo - initial API and implementation

  *******************************************************************************/
 package org.eclipse.sirius.editor.properties.sections.description.selectiondescription;
 
@@ -34,91 +35,91 @@ import org.eclipse.ui.views.properties.tabbed.TabbedPropertySheetPage;
  * A section for the rootExpression property of a SelectionDescription object.
  */
 public class SelectionDescriptionRootExpressionPropertySection extends AbstractTextWithButtonPropertySection implements ContentProposalClient {
-
-    /** Help control of the section. */
-    protected CLabel help;
-
-    /**
-     * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
-     */
-    public void refresh() {
-        super.refresh();
-
-        final String tooltip = getToolTipText();
-        if (tooltip != null && help != null) {
-            help.setToolTipText(getToolTipText());
-        }
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
-     */
-    protected String getDefaultLabelText() {
-        return "RootExpression"; //$NON-NLS-1$
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
-     */
-    protected String getLabelText() {
-        String labelText;
-        labelText = super.getLabelText() + ":"; //$NON-NLS-1$
-        // Start of user code get label text
-
-        // End of user code get label text
-        return labelText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
-     */
-    public EAttribute getFeature() {
-        return DescriptionPackage.eINSTANCE.getSelectionDescription_RootExpression();
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
-     */
-    protected Object getFeatureValue(String newText) {
-        return newText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
-     */
-    protected boolean isEqual(String newText) {
-        return getFeatureAsText().equals(newText);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
-        super.createControls(parent, tabbedPropertySheetPage);
-        /*
-         * We set the color as it's a InterpretedExpression
-         */
-        text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
-
-        text.setToolTipText(getToolTipText());
-
-        help = getWidgetFactory().createCLabel(composite, "");
-        FormData data = new FormData();
+	
+	/** Help control of the section. */
+	protected CLabel help;
+	
+	/**
+	 * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
+	 */
+	public void refresh() {
+		super.refresh();
+
+		final String tooltip = getToolTipText();
+		if (tooltip != null && help != null) {
+			help.setToolTipText(getToolTipText());
+		}
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
+	 */
+	protected String getDefaultLabelText() {
+	    return "RootExpression"; //$NON-NLS-1$
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
+	 */
+	protected String getLabelText() {
+		String labelText;
+		labelText = super.getLabelText() + ":"; //$NON-NLS-1$
+		// Start of user code get label text
+
+	    // End of user code get label text
+	    return labelText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
+	 */
+	public EAttribute getFeature() {
+		return DescriptionPackage.eINSTANCE.getSelectionDescription_RootExpression();
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
+	 */
+	protected Object getFeatureValue(String newText) {
+		return newText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
+	 */
+	protected boolean isEqual(String newText) {
+		return getFeatureAsText().equals(newText);
+	}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
+	    super.createControls(parent, tabbedPropertySheetPage);
+	    /*
+	     * We set the color as it's a InterpretedExpression
+	     */
+	    text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
+	    
+	    text.setToolTipText(getToolTipText());
+	    	    
+	    help = getWidgetFactory().createCLabel(composite,"");
+	    FormData data = new FormData();
         data.top = new FormAttachment(text, 0, SWT.TOP);
-        data.left = new FormAttachment(nameLabel);
+        data.left = new FormAttachment(nameLabel);     
         help.setLayoutData(data);
         help.setImage(getHelpIcon());
-        help.setToolTipText(getToolTipText());
-
-        TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
-
-        // Start of user code create controls
+        help.setToolTipText(getToolTipText());	    
+	    
+         TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
+	    
+	    // Start of user code create controls
 
-        // End of user code create controls
+	    // End of user code create controls
+	    
+	}
 
-    }
-
-    @Override
+	@Override
     protected SelectionListener createButtonListener() {
         return new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
@@ -129,15 +130,15 @@ public class SelectionDescriptionRootExpressionPropertySection extends AbstractT
             }
         };
     }
-
-    /**
-     * {@inheritDoc}
-     */
-    protected String getPropertyDescription() {
-        return "";
-    }
-
-    // Start of user code user operations
-
-    // End of user code user operations
-}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	protected String getPropertyDescription() {
+		return "Required if Tree is ticked\nThis expression will return the root elements displayed in the dialog\nThese elements must also be in the list returned by Candidates Expression";
+	}
+	
+	// Start of user code user operations
+
+	// End of user code user operations
+}
\ No newline at end of file
diff --git a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionTreePropertySection.java b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionTreePropertySection.java
index 58afcee689..0ab51483e3 100644
--- a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionTreePropertySection.java
+++ b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/description/selectiondescription/SelectionDescriptionTreePropertySection.java
@@ -1,11 +1,13 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2013 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2017 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
+ * 
  * Contributors:
  *    Obeo - initial API and implementation
+
  *******************************************************************************/
 package org.eclipse.sirius.editor.properties.sections.description.selectiondescription;
 
@@ -15,6 +17,10 @@ import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.sirius.editor.editorPlugin.SiriusEditor;
 import org.eclipse.sirius.editor.properties.sections.common.AbstractCheckBoxPropertySection;
 import org.eclipse.sirius.viewpoint.description.DescriptionPackage;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.custom.CLabel;
+import org.eclipse.swt.layout.FormAttachment;
+import org.eclipse.swt.layout.FormData;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.ui.views.properties.tabbed.TabbedPropertySheetPage;
 
@@ -27,6 +33,7 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getDefaultLabelText()
      */
+    @Override
     protected String getDefaultLabelText() {
         return "Tree"; //$NON-NLS-1$
     }
@@ -34,6 +41,7 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getLabelText()
      */
+    @Override
     protected String getLabelText() {
         String labelText;
         labelText = super.getLabelText() + "*:"; //$NON-NLS-1$
@@ -46,6 +54,7 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getFeature()
      */
+    @Override
     protected EAttribute getFeature() {
         return DescriptionPackage.eINSTANCE.getSelectionDescription_Tree();
     }
@@ -53,6 +62,7 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getFeatureAsInteger()
      */
+    @Override
     protected String getDefaultFeatureAsText() {
         String value = new String();
         if (eObject.eGet(getFeature()) != null)
@@ -63,6 +73,7 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getFeatureValue(int)
      */
+    @Override
     protected Object getFeatureValue(String newText) {
         return toBoolean(newText);
     }
@@ -70,6 +81,7 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#isEqual(int)
      */
+    @Override
     protected boolean isEqual(String newText) {
         boolean equal = true;
         if (toBoolean(newText) != null)
@@ -94,8 +106,18 @@ public class SelectionDescriptionTreePropertySection extends AbstractCheckBoxPro
     /**
      * {@inheritDoc}
      */
+    @Override
     public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
         super.createControls(parent, tabbedPropertySheetPage);
+        checkbox.setToolTipText("If ticked, Root Expression and Children Expression must be defined");
+
+        CLabel help = getWidgetFactory().createCLabel(composite, "");
+        FormData data = new FormData();
+        data.top = new FormAttachment(checkbox, 0, SWT.TOP);
+        data.left = new FormAttachment(nameLabel);
+        help.setLayoutData(data);
+        help.setImage(getHelpIcon());
+        help.setToolTipText("If ticked, Root Expression and Children Expression must be defined");
         nameLabel.setFont(SiriusEditor.getFontRegistry().get("required"));
     }
 }
diff --git a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection.java b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection.java
index 5a1ac3999e..a0e12014d6 100644
--- a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection.java
+++ b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection.java
@@ -1,11 +1,12 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2013 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2017 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
+ * 
  * Contributors:
- *    Obeo - initial API and implementation
+ *    Obeo - initial API and implementation

  *******************************************************************************/
 package org.eclipse.sirius.editor.properties.sections.tool.panebasedselectionwizarddescription;
 
@@ -34,111 +35,110 @@ import org.eclipse.ui.views.properties.tabbed.TabbedPropertySheetPage;
  * A section for the childrenExpression property of a PaneBasedSelectionWizardDescription object.
  */
 public class PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection extends AbstractTextWithButtonPropertySection implements ContentProposalClient {
-
-    /** Help control of the section. */
-    protected CLabel help;
-
-    /**
-     * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
-     */
-    public void refresh() {
-        super.refresh();
-
-        final String tooltip = getToolTipText();
-        if (tooltip != null && help != null) {
-            help.setToolTipText(getToolTipText());
-        }
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
-     */
-    protected String getDefaultLabelText() {
-        return "ChildrenExpression"; //$NON-NLS-1$
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
-     */
-    protected String getLabelText() {
-        String labelText;
-        labelText = super.getLabelText() + ":"; //$NON-NLS-1$
-        // Start of user code get label text
-
-        // End of user code get label text
-        return labelText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
-     */
-    public EAttribute getFeature() {
-        return ToolPackage.eINSTANCE.getPaneBasedSelectionWizardDescription_ChildrenExpression();
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
-     */
-    protected Object getFeatureValue(String newText) {
-        return newText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
-     */
-    protected boolean isEqual(String newText) {
-        return getFeatureAsText().equals(newText);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
-        super.createControls(parent, tabbedPropertySheetPage);
-        /*
-         * We set the color as it's a InterpretedExpression
-         */
-        text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
-
-        text.setToolTipText(getToolTipText());
-
-        help = getWidgetFactory().createCLabel(composite, "");
-        FormData data = new FormData();
+	
+	/** Help control of the section. */
+	protected CLabel help;
+	
+	/**
+	 * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
+	 */
+	public void refresh() {
+		super.refresh();
+
+		final String tooltip = getToolTipText();
+		if (tooltip != null && help != null) {
+			help.setToolTipText(getToolTipText());
+		}
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
+	 */
+	protected String getDefaultLabelText() {
+	    return "ChildrenExpression"; //$NON-NLS-1$
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
+	 */
+	protected String getLabelText() {
+		String labelText;
+		labelText = super.getLabelText() + ":"; //$NON-NLS-1$
+		// Start of user code get label text
+
+	    // End of user code get label text
+	    return labelText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
+	 */
+	public EAttribute getFeature() {
+		return ToolPackage.eINSTANCE.getPaneBasedSelectionWizardDescription_ChildrenExpression();
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
+	 */
+	protected Object getFeatureValue(String newText) {
+		return newText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
+	 */
+	protected boolean isEqual(String newText) {
+		return getFeatureAsText().equals(newText);
+	}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
+	    super.createControls(parent, tabbedPropertySheetPage);
+	    /*
+	     * We set the color as it's a InterpretedExpression
+	     */
+	    text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
+	    
+	    text.setToolTipText(getToolTipText());
+	    	    
+	    help = getWidgetFactory().createCLabel(composite,"");
+	    FormData data = new FormData();
         data.top = new FormAttachment(text, 0, SWT.TOP);
-        data.left = new FormAttachment(nameLabel);
+        data.left = new FormAttachment(nameLabel);     
         help.setLayoutData(data);
         help.setImage(getHelpIcon());
-        help.setToolTipText(getToolTipText());
-
-        TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
-
-        // Start of user code create controls
+        help.setToolTipText(getToolTipText());	    
+	    
+         TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
+	    
+	    // Start of user code create controls
 
-        // End of user code create controls
+	    // End of user code create controls
+	    
+	}
 
-    }
-
-    @Override
+	@Override
     protected SelectionListener createButtonListener() {
         return new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
-                TextWithContentProposalDialog dialog = new TextWithContentProposalDialog(composite.getShell(), PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection.this,
-                        text.getText());
+                TextWithContentProposalDialog dialog = new TextWithContentProposalDialog(composite.getShell(), PaneBasedSelectionWizardDescriptionChildrenExpressionPropertySection.this, text.getText());
                 dialog.open();
                 text.setText(dialog.getResult());
                 handleTextModified();
             }
         };
     }
-
-    /**
-     * {@inheritDoc}
-     */
-    protected String getPropertyDescription() {
-        return "";
-    }
-
-    // Start of user code user operations
-
-    // End of user code user operations
-}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	protected String getPropertyDescription() {
+		return "Required if Tree is ticked\nThis expression will return the children of a candidate element and will be evaluated recursively on each candidate from the root elements\nThese elements must also be in the list returned by Candidates Expression";
+	}
+	
+	// Start of user code user operations
+
+	// End of user code user operations
+}
\ No newline at end of file
diff --git a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionRootExpressionPropertySection.java b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionRootExpressionPropertySection.java
index 97a380f869..2661387838 100644
--- a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionRootExpressionPropertySection.java
+++ b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionRootExpressionPropertySection.java
@@ -1,11 +1,12 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2013 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2017 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
+ * 
  * Contributors:
- *    Obeo - initial API and implementation
+ *    Obeo - initial API and implementation

  *******************************************************************************/
 package org.eclipse.sirius.editor.properties.sections.tool.panebasedselectionwizarddescription;
 
@@ -34,91 +35,91 @@ import org.eclipse.ui.views.properties.tabbed.TabbedPropertySheetPage;
  * A section for the rootExpression property of a PaneBasedSelectionWizardDescription object.
  */
 public class PaneBasedSelectionWizardDescriptionRootExpressionPropertySection extends AbstractTextWithButtonPropertySection implements ContentProposalClient {
-
-    /** Help control of the section. */
-    protected CLabel help;
-
-    /**
-     * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
-     */
-    public void refresh() {
-        super.refresh();
-
-        final String tooltip = getToolTipText();
-        if (tooltip != null && help != null) {
-            help.setToolTipText(getToolTipText());
-        }
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
-     */
-    protected String getDefaultLabelText() {
-        return "RootExpression"; //$NON-NLS-1$
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
-     */
-    protected String getLabelText() {
-        String labelText;
-        labelText = super.getLabelText() + ":"; //$NON-NLS-1$
-        // Start of user code get label text
-
-        // End of user code get label text
-        return labelText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
-     */
-    public EAttribute getFeature() {
-        return ToolPackage.eINSTANCE.getPaneBasedSelectionWizardDescription_RootExpression();
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
-     */
-    protected Object getFeatureValue(String newText) {
-        return newText;
-    }
-
-    /**
-     * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
-     */
-    protected boolean isEqual(String newText) {
-        return getFeatureAsText().equals(newText);
-    }
-
-    /**
-     * {@inheritDoc}
-     */
-    public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
-        super.createControls(parent, tabbedPropertySheetPage);
-        /*
-         * We set the color as it's a InterpretedExpression
-         */
-        text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
-
-        text.setToolTipText(getToolTipText());
-
-        help = getWidgetFactory().createCLabel(composite, "");
-        FormData data = new FormData();
+	
+	/** Help control of the section. */
+	protected CLabel help;
+	
+	/**
+	 * @see org.eclipse.ui.views.properties.tabbed.view.ITabbedPropertySection#refresh()
+	 */
+	public void refresh() {
+		super.refresh();
+
+		final String tooltip = getToolTipText();
+		if (tooltip != null && help != null) {
+			help.setToolTipText(getToolTipText());
+		}
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getDefaultLabelText()
+	 */
+	protected String getDefaultLabelText() {
+	    return "RootExpression"; //$NON-NLS-1$
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getLabelText()
+	 */
+	protected String getLabelText() {
+		String labelText;
+		labelText = super.getLabelText() + ":"; //$NON-NLS-1$
+		// Start of user code get label text
+
+	    // End of user code get label text
+	    return labelText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeature()
+	 */
+	public EAttribute getFeature() {
+		return ToolPackage.eINSTANCE.getPaneBasedSelectionWizardDescription_RootExpression();
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#getFeatureValue(String)
+	 */
+	protected Object getFeatureValue(String newText) {
+		return newText;
+	}
+	
+	/**
+	 * @see org.eclipse.sirius.editor.properties.sections.AbstractTextWithButtonPropertySection#isEqual(String)
+	 */
+	protected boolean isEqual(String newText) {
+		return getFeatureAsText().equals(newText);
+	}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
+	    super.createControls(parent, tabbedPropertySheetPage);
+	    /*
+	     * We set the color as it's a InterpretedExpression
+	     */
+	    text.setBackground(SiriusEditor.getColorRegistry().get("yellow"));
+	    
+	    text.setToolTipText(getToolTipText());
+	    	    
+	    help = getWidgetFactory().createCLabel(composite,"");
+	    FormData data = new FormData();
         data.top = new FormAttachment(text, 0, SWT.TOP);
-        data.left = new FormAttachment(nameLabel);
+        data.left = new FormAttachment(nameLabel);     
         help.setLayoutData(data);
         help.setImage(getHelpIcon());
-        help.setToolTipText(getToolTipText());
-
-        TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
-
-        // Start of user code create controls
+        help.setToolTipText(getToolTipText());	    
+	    
+         TypeContentProposalProvider.bindPluginsCompletionProcessors(this, text);
+	    
+	    // Start of user code create controls
 
-        // End of user code create controls
+	    // End of user code create controls
+	    
+	}
 
-    }
-
-    @Override
+	@Override
     protected SelectionListener createButtonListener() {
         return new SelectionAdapter() {
             public void widgetSelected(SelectionEvent e) {
@@ -129,15 +130,15 @@ public class PaneBasedSelectionWizardDescriptionRootExpressionPropertySection ex
             }
         };
     }
-
-    /**
-     * {@inheritDoc}
-     */
-    protected String getPropertyDescription() {
-        return "";
-    }
-
-    // Start of user code user operations
-
-    // End of user code user operations
-}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	protected String getPropertyDescription() {
+		return "Required if Tree is ticked\nThis expression will return the root elements displayed in the dialog\nThese elements must also be in the list returned by Candidates Expression";
+	}
+	
+	// Start of user code user operations
+
+	// End of user code user operations
+}
\ No newline at end of file
diff --git a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionTreePropertySection.java b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionTreePropertySection.java
index 3896e5024f..237f26a896 100644
--- a/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionTreePropertySection.java
+++ b/plugins/org.eclipse.sirius.editor/src-gen/org/eclipse/sirius/editor/properties/sections/tool/panebasedselectionwizarddescription/PaneBasedSelectionWizardDescriptionTreePropertySection.java
@@ -1,11 +1,13 @@
 /*******************************************************************************
- * Copyright (c) 2007, 2013 THALES GLOBAL SERVICES.
+ * Copyright (c) 2007, 2017 THALES GLOBAL SERVICES.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
+ * 
  * Contributors:
  *    Obeo - initial API and implementation
+
  *******************************************************************************/
 package org.eclipse.sirius.editor.properties.sections.tool.panebasedselectionwizarddescription;
 
@@ -14,6 +16,10 @@ import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.sirius.editor.editorPlugin.SiriusEditor;
 import org.eclipse.sirius.editor.properties.sections.common.AbstractCheckBoxPropertySection;
 import org.eclipse.sirius.viewpoint.description.tool.ToolPackage;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.custom.CLabel;
+import org.eclipse.swt.layout.FormAttachment;
+import org.eclipse.swt.layout.FormData;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.ui.views.properties.tabbed.TabbedPropertySheetPage;
 
@@ -26,6 +32,7 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getDefaultLabelText()
      */
+    @Override
     protected String getDefaultLabelText() {
         return "Tree"; //$NON-NLS-1$
     }
@@ -33,6 +40,7 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getLabelText()
      */
+    @Override
     protected String getLabelText() {
         String labelText;
         labelText = super.getLabelText() + "*:"; //$NON-NLS-1$
@@ -45,6 +53,7 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getFeature()
      */
+    @Override
     protected EAttribute getFeature() {
         return ToolPackage.eINSTANCE.getPaneBasedSelectionWizardDescription_Tree();
     }
@@ -52,6 +61,7 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getFeatureAsInteger()
      */
+    @Override
     protected String getDefaultFeatureAsText() {
         String value = new String();
         if (eObject.eGet(getFeature()) != null)
@@ -62,6 +72,7 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#getFeatureValue(int)
      */
+    @Override
     protected Object getFeatureValue(String newText) {
         return toBoolean(newText);
     }
@@ -69,6 +80,7 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * @see org.eclipse.sirius.editor.properties.sections.AbstractCheckBoxPropertySection#isEqual(int)
      */
+    @Override
     protected boolean isEqual(String newText) {
         boolean equal = true;
         if (toBoolean(newText) != null)
@@ -93,8 +105,18 @@ public class PaneBasedSelectionWizardDescriptionTreePropertySection extends Abst
     /**
      * {@inheritDoc}
      */
+    @Override
     public void createControls(Composite parent, TabbedPropertySheetPage tabbedPropertySheetPage) {
         super.createControls(parent, tabbedPropertySheetPage);
+        checkbox.setToolTipText("If ticked, Root Expression and Children Expression must be defined");
+
+        CLabel help = getWidgetFactory().createCLabel(composite, "");
+        FormData data = new FormData();
+        data.top = new FormAttachment(checkbox, 0, SWT.TOP);
+        data.left = new FormAttachment(nameLabel);
+        help.setLayoutData(data);
+        help.setImage(getHelpIcon());
+        help.setToolTipText("If ticked, Root Expression and Children Expression must be defined");
         nameLabel.setFont(SiriusEditor.getFontRegistry().get("required"));
     }
 }
diff --git a/plugins/org.eclipse.sirius/model/viewpoint.genmodel b/plugins/org.eclipse.sirius/model/viewpoint.genmodel
index 8df6bd8eb2..eda9094756 100644
--- a/plugins/org.eclipse.sirius/model/viewpoint.genmodel
+++ b/plugins/org.eclipse.sirius/model/viewpoint.genmodel
@@ -351,9 +351,12 @@
       <genClasses image="false" ecoreClass="viewpoint.ecore#//description/SelectionDescription">
         <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/candidatesExpression"/>
         <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/multiple"/>
-        <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/tree"/>
-        <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/rootExpression"/>
-        <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/childrenExpression"/>
+        <genFeatures createChild="false" propertyCategory="General" propertyDescription="If ticked, Root Expression and Children Expression must be defined"
+            ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/tree"/>
+        <genFeatures createChild="false" propertyCategory="General" propertyDescription="Required if Tree is ticked\nThis expression will return the root elements displayed in the dialog\nThese elements must also be in the list returned by Candidates Expression"
+            ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/rootExpression"/>
+        <genFeatures createChild="false" propertyCategory="General" propertyDescription="Required if Tree is ticked\nThis expression will return the children of a candidate element and will be evaluated recursively on each candidate from the root elements\nThese elements must also be in the list returned by Candidates Expression"
+            ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/childrenExpression"/>
         <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/SelectionDescription/message"/>
       </genClasses>
       <genClasses image="false" ecoreClass="viewpoint.ecore#//description/ColorDescription"/>
@@ -517,9 +520,12 @@
           <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/message"/>
           <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/choiceOfValuesMessage"/>
           <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/candidatesExpression"/>
-          <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/tree"/>
-          <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/rootExpression"/>
-          <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/childrenExpression"/>
+          <genFeatures createChild="false" propertyCategory="General" propertyDescription="If ticked, Root Expression and Children Expression must be defined"
+              ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/tree"/>
+          <genFeatures createChild="false" propertyCategory="General" propertyDescription="Required if Tree is ticked\nThis expression will return the root elements displayed in the dialog\nThese elements must also be in the list returned by Candidates Expression"
+              ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/rootExpression"/>
+          <genFeatures createChild="false" propertyCategory="General" propertyDescription="Required if Tree is ticked\nThis expression will return the children of a candidate element and will be evaluated recursively on each candidate from the root elements\nThese elements must also be in the list returned by Candidates Expression"
+              ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/childrenExpression"/>
           <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/selectedValuesMessage"/>
           <genFeatures createChild="false" propertyCategory="General" ecoreFeature="ecore:EAttribute viewpoint.ecore#//description/tool/PaneBasedSelectionWizardDescription/preSelectedCandidatesExpression"/>
         </genClasses>