[501680] Add support for style for the reference widget

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=501680
Change-Id: I563ed5eb2fb9946778aa3344c872e64349718b46
Signed-off-by: Stéphane Bégaudeau <stephane.begaudeau@obeo.fr>

44 files changed, 1704 insertions, 98 deletions

diff --git a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
index 0b8af10f53..ab683ca93e 100644
--- a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
+++ b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.html
@@ -527,6 +527,18 @@
 				<code>labelFontSizeExpression</code> since both of them were already treated as expression.
 			</li>
 		</ul>
+		<h4 id="Changesinorg.eclipse.sirius.ui.properties">Changes in 
+			<code>org.eclipse.sirius.ui.properties</code>
+		</h4>
+		<ul>
+			<li><span class="label label-success">Added</span> Four utility classes have been added as API in the package 
+				<code>org.eclipse.sirius.ui.properties.api</code> in order to help with the transformation of the description of custom widgets. The class 
+				<code>AbstractDescriptionConverter</code> can now be used as superclass for all the converters. The classes 
+				<code>DefautDescriptionConverter</code>, 
+				<code>DefautStyleDescriptionConverter</code> and 
+				<code>DefautDescriptionWithInitialOperationConverter</code>, now accessible, should handle most of the use cases. 
+			</li>
+		</ul>
 		<h4 id="Changesinorg.eclipse.sirius.ecore.extender">Changes in 
 			<code>org.eclipse.sirius.ecore.extender</code>
 		</h4>
diff --git a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
index 907889207b..b87e1ad147 100644
--- a/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
+++ b/plugins/org.eclipse.sirius.doc/doc/Release_Notes.textile
@@ -126,6 +126,10 @@ h4. Changes in @org.eclipse.sirius.properties@
 * <span class="label label-info">Modified</span> The property @domainClassExpression@ has been renamed into @iterableExpression@.
 * <span class="label label-info">Modified</span> The properties @fontSize@ and @labelFontSize@ have been renamed into @fontSizeExpression@ and @labelFontSizeExpression@ since both of them were already treated as expression.
 
+h4. Changes in @org.eclipse.sirius.ui.properties@
+
+* <span class="label label-success">Added</span> Four utility classes have been added as API in the package @org.eclipse.sirius.ui.properties.api@ in order to help with the transformation of the description of custom widgets. The class @AbstractDescriptionConverter@ can now be used as superclass for all the converters. The classes @DefautDescriptionConverter@, @DefautStyleDescriptionConverter@ and @DefautDescriptionWithInitialOperationConverter@, now accessible, should handle most of the use cases. 
+
 h4. Changes in @org.eclipse.sirius.ecore.extender@
 
 * <span class="label label-info">Modified</span> The message @org.eclipse.sirius.ecore.extender.business.api.permission.exception.LockedInstanceException.PERMISSION_ISSUE_MESSAGE@ has been modified. You should now use the @MessageFormat@. Example: @LockedInstanceException.PERMISSION_ISSUE_MESSAGE + getText(lockedElements)@ must be replaced by @MessageFormat.format(LockedInstanceException.PERMISSION_ISSUE_MESSAGE, getText(lockedElements))@.
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceDescription_conditionalStyles_ExtReferenceWidgetConditionalStyle.gif b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceDescription_conditionalStyles_ExtReferenceWidgetConditionalStyle.gif
new file mode 100644
index 0000000000..e7e23a6913
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceDescription_conditionalStyles_ExtReferenceWidgetConditionalStyle.gif
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceDescription_style_ExtReferenceWidgetStyle.gif b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceDescription_style_ExtReferenceWidgetStyle.gif
new file mode 100644
index 0000000000..e9a6bd966a
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceDescription_style_ExtReferenceWidgetStyle.gif
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceWidgetConditionalStyle_style_ExtReferenceWidgetStyle.gif b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceWidgetConditionalStyle_style_ExtReferenceWidgetStyle.gif
new file mode 100644
index 0000000000..e9a6bd966a
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/ctool16/CreateExtReferenceWidgetConditionalStyle_style_ExtReferenceWidgetStyle.gif
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/obj16/ExtReferenceWidgetConditionalStyle.gif b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/obj16/ExtReferenceWidgetConditionalStyle.gif
new file mode 100644
index 0000000000..e7e23a6913
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/obj16/ExtReferenceWidgetConditionalStyle.gif
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/obj16/ExtReferenceWidgetStyle.gif b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/obj16/ExtReferenceWidgetStyle.gif
new file mode 100644
index 0000000000..e9a6bd966a
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/icons/full/obj16/ExtReferenceWidgetStyle.gif
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/plugin.properties b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/plugin.properties
index a0a91739f5..1cdfba1113 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/plugin.properties
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/plugin.properties
@@ -30,3 +30,8 @@ _UI_Unknown_feature = Unspecified
 
 _UI_ExtReferenceDescription_referenceNameExpression_feature = Reference Name Expression
 _UI_ExtReferenceDescription_referenceOwnerExpression_feature = Reference Owner Expression
+_UI_ExtReferenceWidgetStyle_type = Ext Reference Widget Style
+_UI_ExtReferenceWidgetConditionalStyle_type = Ext Reference Widget Conditional Style
+_UI_ExtReferenceDescription_style_feature = Style
+_UI_ExtReferenceDescription_conditionalStyles_feature = Conditional Styles
+_UI_ExtReferenceWidgetConditionalStyle_style_feature = Style
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceDescriptionItemProvider.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceDescriptionItemProvider.java
index fa2be69ba7..c2758628e3 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceDescriptionItemProvider.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceDescriptionItemProvider.java
@@ -16,6 +16,7 @@ import java.util.List;
 
 import org.eclipse.emf.common.notify.AdapterFactory;
 import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.edit.provider.ComposeableAdapterFactory;
 import org.eclipse.emf.edit.provider.IItemPropertyDescriptor;
 import org.eclipse.emf.edit.provider.IItemStyledLabelProvider;
@@ -23,6 +24,7 @@ import org.eclipse.emf.edit.provider.ItemPropertyDescriptor;
 import org.eclipse.emf.edit.provider.StyledString;
 import org.eclipse.emf.edit.provider.ViewerNotification;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferenceFactory;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
 import org.eclipse.sirius.properties.provider.WidgetDescriptionItemProvider;
 
@@ -30,7 +32,7 @@ import org.eclipse.sirius.properties.provider.WidgetDescriptionItemProvider;
  * This is the item provider adapter for a
  * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription}
  * object. <!-- begin-user-doc --> <!-- end-user-doc -->
- * 
+ *
  * @generated
  */
 public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemProvider implements IItemStyledLabelProvider {
@@ -64,7 +66,7 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
     /**
      * This adds a property descriptor for the Reference Name Expression
      * feature. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     protected void addReferenceNameExpressionPropertyDescriptor(Object object) {
@@ -77,7 +79,7 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
     /**
      * This adds a property descriptor for the Reference Owner Expression
      * feature. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     protected void addReferenceOwnerExpressionPropertyDescriptor(Object object) {
@@ -88,9 +90,43 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
     }
 
     /**
+     * This specifies how to implement {@link #getChildren} and is used to
+     * deduce an appropriate feature for an
+     * {@link org.eclipse.emf.edit.command.AddCommand},
+     * {@link org.eclipse.emf.edit.command.RemoveCommand} or
+     * {@link org.eclipse.emf.edit.command.MoveCommand} in
+     * {@link #createCommand}. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Collection<? extends EStructuralFeature> getChildrenFeatures(Object object) {
+        if (childrenFeatures == null) {
+            super.getChildrenFeatures(object);
+            childrenFeatures.add(PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_DESCRIPTION__STYLE);
+            childrenFeatures.add(PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES);
+        }
+        return childrenFeatures;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    protected EStructuralFeature getChildFeature(Object object, Object child) {
+        // Check the type of the specified child object and return the proper
+        // feature to use for
+        // adding (see {@link AddCommand}) it as a child.
+
+        return super.getChildFeature(object, child);
+    }
+
+    /**
      * This returns ExtReferenceDescription.gif. <!-- begin-user-doc --> <!--
      * end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -101,7 +137,7 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
     /**
      * This returns the label text for the adapted class. <!-- begin-user-doc
      * --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -132,7 +168,7 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
      * update any cached children and by creating a viewer notification, which
      * it passes to {@link #fireNotifyChanged}. <!-- begin-user-doc --> <!--
      * end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -144,6 +180,10 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION:
             fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), false, true));
             return;
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE:
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES:
+            fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), true, false));
+            return;
         }
         super.notifyChanged(notification);
     }
@@ -158,6 +198,12 @@ public class ExtReferenceDescriptionItemProvider extends WidgetDescriptionItemPr
     @Override
     protected void collectNewChildDescriptors(Collection<Object> newChildDescriptors, Object object) {
         super.collectNewChildDescriptors(newChildDescriptors, object);
+
+        newChildDescriptors.add(
+                createChildParameter(PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_DESCRIPTION__STYLE, PropertiesExtWidgetsReferenceFactory.eINSTANCE.createExtReferenceWidgetStyle()));
+
+        newChildDescriptors.add(createChildParameter(PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES,
+                PropertiesExtWidgetsReferenceFactory.eINSTANCE.createExtReferenceWidgetConditionalStyle()));
     }
 
 }
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceWidgetConditionalStyleItemProvider.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceWidgetConditionalStyleItemProvider.java
new file mode 100644
index 0000000000..e748328237
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceWidgetConditionalStyleItemProvider.java
@@ -0,0 +1,170 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.properties.ext.widgets.reference.propertiesextwidgetsreference.provider;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.eclipse.emf.common.notify.AdapterFactory;
+import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.ecore.EStructuralFeature;
+import org.eclipse.emf.edit.provider.IItemPropertyDescriptor;
+import org.eclipse.emf.edit.provider.IItemStyledLabelProvider;
+import org.eclipse.emf.edit.provider.StyledString;
+import org.eclipse.emf.edit.provider.ViewerNotification;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferenceFactory;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
+import org.eclipse.sirius.properties.provider.WidgetConditionalStyleItemProvider;
+
+/**
+ * This is the item provider adapter for a
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle}
+ * object. <!-- begin-user-doc --> <!-- end-user-doc -->
+ *
+ * @generated
+ */
+public class ExtReferenceWidgetConditionalStyleItemProvider extends WidgetConditionalStyleItemProvider implements IItemStyledLabelProvider {
+    /**
+     * This constructs an instance from a factory and a notifier. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    public ExtReferenceWidgetConditionalStyleItemProvider(AdapterFactory adapterFactory) {
+        super(adapterFactory);
+    }
+
+    /**
+     * This returns the property descriptors for the adapted class. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public List<IItemPropertyDescriptor> getPropertyDescriptors(Object object) {
+        if (itemPropertyDescriptors == null) {
+            super.getPropertyDescriptors(object);
+
+        }
+        return itemPropertyDescriptors;
+    }
+
+    /**
+     * This specifies how to implement {@link #getChildren} and is used to
+     * deduce an appropriate feature for an
+     * {@link org.eclipse.emf.edit.command.AddCommand},
+     * {@link org.eclipse.emf.edit.command.RemoveCommand} or
+     * {@link org.eclipse.emf.edit.command.MoveCommand} in
+     * {@link #createCommand}. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Collection<? extends EStructuralFeature> getChildrenFeatures(Object object) {
+        if (childrenFeatures == null) {
+            super.getChildrenFeatures(object);
+            childrenFeatures.add(PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE);
+        }
+        return childrenFeatures;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    protected EStructuralFeature getChildFeature(Object object, Object child) {
+        // Check the type of the specified child object and return the proper
+        // feature to use for
+        // adding (see {@link AddCommand}) it as a child.
+
+        return super.getChildFeature(object, child);
+    }
+
+    /**
+     * This returns ExtReferenceWidgetConditionalStyle.gif. <!-- begin-user-doc
+     * --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Object getImage(Object object) {
+        return overlayImage(object, getResourceLocator().getImage("full/obj16/ExtReferenceWidgetConditionalStyle")); //$NON-NLS-1$
+    }
+
+    /**
+     * This returns the label text for the adapted class. <!-- begin-user-doc
+     * --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public String getText(Object object) {
+        return ((StyledString) getStyledText(object)).getString();
+    }
+
+    /**
+     * This returns the label styled text for the adapted class. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Object getStyledText(Object object) {
+        String label = ((ExtReferenceWidgetConditionalStyle) object).getPreconditionExpression();
+        StyledString styledLabel = new StyledString();
+        if (label == null || label.length() == 0) {
+            styledLabel.append(getString("_UI_ExtReferenceWidgetConditionalStyle_type"), StyledString.Style.QUALIFIER_STYLER); //$NON-NLS-1$
+        } else {
+            styledLabel.append(getString("_UI_ExtReferenceWidgetConditionalStyle_type"), StyledString.Style.QUALIFIER_STYLER).append(" " + label); //$NON-NLS-1$ //$NON-NLS-2$
+        }
+        return styledLabel;
+    }
+
+    /**
+     * This handles model notifications by calling {@link #updateChildren} to
+     * update any cached children and by creating a viewer notification, which
+     * it passes to {@link #fireNotifyChanged}. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public void notifyChanged(Notification notification) {
+        updateChildren(notification);
+
+        switch (notification.getFeatureID(ExtReferenceWidgetConditionalStyle.class)) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE:
+            fireNotifyChanged(new ViewerNotification(notification, notification.getNotifier(), true, false));
+            return;
+        }
+        super.notifyChanged(notification);
+    }
+
+    /**
+     * This adds {@link org.eclipse.emf.edit.command.CommandParameter}s
+     * describing the children that can be created under this object. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    protected void collectNewChildDescriptors(Collection<Object> newChildDescriptors, Object object) {
+        super.collectNewChildDescriptors(newChildDescriptors, object);
+
+        newChildDescriptors.add(createChildParameter(PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE,
+                PropertiesExtWidgetsReferenceFactory.eINSTANCE.createExtReferenceWidgetStyle()));
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceWidgetStyleItemProvider.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceWidgetStyleItemProvider.java
new file mode 100644
index 0000000000..69086a0398
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/ExtReferenceWidgetStyleItemProvider.java
@@ -0,0 +1,124 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.properties.ext.widgets.reference.propertiesextwidgetsreference.provider;
+
+import java.util.Collection;
+import java.util.List;
+
+import org.eclipse.emf.common.notify.AdapterFactory;
+import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.edit.provider.IItemPropertyDescriptor;
+import org.eclipse.emf.edit.provider.IItemStyledLabelProvider;
+import org.eclipse.emf.edit.provider.StyledString;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
+import org.eclipse.sirius.properties.provider.WidgetStyleItemProvider;
+
+/**
+ * This is the item provider adapter for a
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle}
+ * object. <!-- begin-user-doc --> <!-- end-user-doc -->
+ *
+ * @generated
+ */
+public class ExtReferenceWidgetStyleItemProvider extends WidgetStyleItemProvider implements IItemStyledLabelProvider {
+    /**
+     * This constructs an instance from a factory and a notifier. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    public ExtReferenceWidgetStyleItemProvider(AdapterFactory adapterFactory) {
+        super(adapterFactory);
+    }
+
+    /**
+     * This returns the property descriptors for the adapted class. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public List<IItemPropertyDescriptor> getPropertyDescriptors(Object object) {
+        if (itemPropertyDescriptors == null) {
+            super.getPropertyDescriptors(object);
+
+        }
+        return itemPropertyDescriptors;
+    }
+
+    /**
+     * This returns ExtReferenceWidgetStyle.gif. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Object getImage(Object object) {
+        return overlayImage(object, getResourceLocator().getImage("full/obj16/ExtReferenceWidgetStyle")); //$NON-NLS-1$
+    }
+
+    /**
+     * This returns the label text for the adapted class. <!-- begin-user-doc
+     * --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public String getText(Object object) {
+        return ((StyledString) getStyledText(object)).getString();
+    }
+
+    /**
+     * This returns the label styled text for the adapted class. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Object getStyledText(Object object) {
+        String label = ((ExtReferenceWidgetStyle) object).getLabelFontNameExpression();
+        StyledString styledLabel = new StyledString();
+        if (label == null || label.length() == 0) {
+            styledLabel.append(getString("_UI_ExtReferenceWidgetStyle_type"), StyledString.Style.QUALIFIER_STYLER); //$NON-NLS-1$
+        } else {
+            styledLabel.append(getString("_UI_ExtReferenceWidgetStyle_type"), StyledString.Style.QUALIFIER_STYLER).append(" " + label); //$NON-NLS-1$ //$NON-NLS-2$
+        }
+        return styledLabel;
+    }
+
+    /**
+     * This handles model notifications by calling {@link #updateChildren} to
+     * update any cached children and by creating a viewer notification, which
+     * it passes to {@link #fireNotifyChanged}. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public void notifyChanged(Notification notification) {
+        updateChildren(notification);
+        super.notifyChanged(notification);
+    }
+
+    /**
+     * This adds {@link org.eclipse.emf.edit.command.CommandParameter}s
+     * describing the children that can be created under this object. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    protected void collectNewChildDescriptors(Collection<Object> newChildDescriptors, Object object) {
+        super.collectNewChildDescriptors(newChildDescriptors, object);
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesExtWidgetsReferenceItemProviderAdapterFactory.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesExtWidgetsReferenceItemProviderAdapterFactory.java
index e60abe78fa..586d4f75fe 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesExtWidgetsReferenceItemProviderAdapterFactory.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesExtWidgetsReferenceItemProviderAdapterFactory.java
@@ -52,15 +52,15 @@ import org.eclipse.sirius.properties.util.PropertiesSwitch;
  * adapters also support Eclipse property sheets. Note that most of the adapters
  * are shared among multiple instances. <!-- begin-user-doc --> <!--
  * end-user-doc -->
- * 
+ *
  * @generated
  */
-public class PropertiesExtWidgetsReferenceItemProviderAdapterFactory extends PropertiesExtWidgetsReferenceAdapterFactory implements ComposeableAdapterFactory, IChangeNotifier, IDisposable,
-IChildCreationExtender {
+public class PropertiesExtWidgetsReferenceItemProviderAdapterFactory extends PropertiesExtWidgetsReferenceAdapterFactory
+        implements ComposeableAdapterFactory, IChangeNotifier, IDisposable, IChildCreationExtender {
     /**
      * This keeps track of the root adapter factory that delegates to this
      * adapter factory. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     protected ComposedAdapterFactory parentAdapterFactory;
@@ -77,7 +77,7 @@ IChildCreationExtender {
     /**
      * This helps manage the child creation extenders. <!-- begin-user-doc -->
      * <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     protected ChildCreationExtenderManager childCreationExtenderManager = new ChildCreationExtenderManager(PropertiesextwidgetsreferenceEditPlugin.INSTANCE,
@@ -87,7 +87,7 @@ IChildCreationExtender {
      * This keeps track of all the supported types checked by
      * {@link #isFactoryForType isFactoryForType}. <!-- begin-user-doc --> <!--
      * end-user-doc -->
-     * 
+     *
      * @generated
      */
     protected Collection<Object> supportedTypes = new ArrayList<Object>();
@@ -111,7 +111,7 @@ IChildCreationExtender {
      * This keeps track of the one adapter used for all
      * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription}
      * instances. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     protected ExtReferenceDescriptionItemProvider extReferenceDescriptionItemProvider;
@@ -120,7 +120,7 @@ IChildCreationExtender {
      * This creates an adapter for a
      * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription}
      * . <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -133,6 +133,56 @@ IChildCreationExtender {
     }
 
     /**
+     * This keeps track of the one adapter used for all
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle}
+     * instances. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    protected ExtReferenceWidgetStyleItemProvider extReferenceWidgetStyleItemProvider;
+
+    /**
+     * This creates an adapter for a
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle}
+     * . <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Adapter createExtReferenceWidgetStyleAdapter() {
+        if (extReferenceWidgetStyleItemProvider == null) {
+            extReferenceWidgetStyleItemProvider = new ExtReferenceWidgetStyleItemProvider(this);
+        }
+
+        return extReferenceWidgetStyleItemProvider;
+    }
+
+    /**
+     * This keeps track of the one adapter used for all
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle}
+     * instances. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    protected ExtReferenceWidgetConditionalStyleItemProvider extReferenceWidgetConditionalStyleItemProvider;
+
+    /**
+     * This creates an adapter for a
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle}
+     * . <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Adapter createExtReferenceWidgetConditionalStyleAdapter() {
+        if (extReferenceWidgetConditionalStyleItemProvider == null) {
+            extReferenceWidgetConditionalStyleItemProvider = new ExtReferenceWidgetConditionalStyleItemProvider(this);
+        }
+
+        return extReferenceWidgetConditionalStyleItemProvider;
+    }
+
+    /**
      * This returns the root adapter factory that contains this factory. <!--
      * begin-user-doc --> <!-- end-user-doc -->
      *
@@ -156,7 +206,7 @@ IChildCreationExtender {
 
     /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -167,7 +217,7 @@ IChildCreationExtender {
     /**
      * This implementation substitutes the factory itself as the key for the
      * adapter. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -177,7 +227,7 @@ IChildCreationExtender {
 
     /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -194,7 +244,7 @@ IChildCreationExtender {
 
     /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     public List<IChildCreationExtender> getChildCreationExtenders() {
@@ -203,7 +253,7 @@ IChildCreationExtender {
 
     /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -213,7 +263,7 @@ IChildCreationExtender {
 
     /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -223,7 +273,7 @@ IChildCreationExtender {
 
     /**
      * This adds a listener. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -233,7 +283,7 @@ IChildCreationExtender {
 
     /**
      * This removes a listener. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     @Override
@@ -268,6 +318,12 @@ IChildCreationExtender {
         if (extReferenceDescriptionItemProvider != null) {
             extReferenceDescriptionItemProvider.dispose();
         }
+        if (extReferenceWidgetStyleItemProvider != null) {
+            extReferenceWidgetStyleItemProvider.dispose();
+        }
+        if (extReferenceWidgetConditionalStyleItemProvider != null) {
+            extReferenceWidgetConditionalStyleItemProvider.dispose();
+        }
     }
 
     /**
@@ -280,14 +336,14 @@ IChildCreationExtender {
         /**
          * The switch for creating child descriptors specific to each extended
          * class. <!-- begin-user-doc --> <!-- end-user-doc -->
-         * 
+         *
          * @generated
          */
         protected static class CreationSwitch extends PropertiesSwitch<Object> {
             /**
              * The child descriptors being populated. <!-- begin-user-doc -->
              * <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             protected List<Object> newChildDescriptors;
@@ -295,7 +351,7 @@ IChildCreationExtender {
             /**
              * The domain in which to create the children. <!-- begin-user-doc
              * --> <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             protected EditingDomain editingDomain;
@@ -303,7 +359,7 @@ IChildCreationExtender {
             /**
              * Creates the a switch for populating child descriptors in the
              * given domain. <!-- begin-user-doc --> <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             CreationSwitch(List<Object> newChildDescriptors, EditingDomain editingDomain) {
@@ -313,7 +369,7 @@ IChildCreationExtender {
 
             /**
              * <!-- begin-user-doc --> <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             @Override
@@ -325,20 +381,20 @@ IChildCreationExtender {
 
             /**
              * <!-- begin-user-doc --> <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             @Override
             public Object caseContainerDescription(ContainerDescription object) {
                 newChildDescriptors
-                .add(createChildParameter(PropertiesPackage.Literals.CONTAINER_DESCRIPTION__CONTROLS, PropertiesExtWidgetsReferenceFactory.eINSTANCE.createExtReferenceDescription()));
+                        .add(createChildParameter(PropertiesPackage.Literals.CONTAINER_DESCRIPTION__CONTROLS, PropertiesExtWidgetsReferenceFactory.eINSTANCE.createExtReferenceDescription()));
 
                 return null;
             }
 
             /**
              * <!-- begin-user-doc --> <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             @Override
@@ -350,7 +406,7 @@ IChildCreationExtender {
 
             /**
              * <!-- begin-user-doc --> <!-- end-user-doc -->
-             * 
+             *
              * @generated
              */
             protected CommandParameter createChildParameter(Object feature, Object child) {
@@ -361,7 +417,7 @@ IChildCreationExtender {
 
         /**
          * <!-- begin-user-doc --> <!-- end-user-doc -->
-         * 
+         *
          * @generated
          */
         @Override
@@ -373,7 +429,7 @@ IChildCreationExtender {
 
         /**
          * <!-- begin-user-doc --> <!-- end-user-doc -->
-         * 
+         *
          * @generated
          */
         @Override
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesextwidgetsreferenceEditPlugin.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesextwidgetsreferenceEditPlugin.java
index a21fad0800..52dcd58bf3 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesextwidgetsreferenceEditPlugin.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference.edit/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/provider/PropertiesextwidgetsreferenceEditPlugin.java
@@ -20,7 +20,7 @@ import org.eclipse.sirius.viewpoint.provider.SiriusEditPlugin;
 /**
  * This is the central singleton for the Properties-ext-widgets-reference edit
  * plugin. <!-- begin-user-doc --> <!-- end-user-doc -->
- * 
+ *
  * @generated
  */
 public final class PropertiesextwidgetsreferenceEditPlugin extends EMFPlugin {
@@ -42,7 +42,7 @@ public final class PropertiesextwidgetsreferenceEditPlugin extends EMFPlugin {
 
     /**
      * Create the instance. <!-- begin-user-doc --> <!-- end-user-doc -->
-     * 
+     *
      * @generated
      */
     public PropertiesextwidgetsreferenceEditPlugin() {
@@ -52,7 +52,7 @@ public final class PropertiesextwidgetsreferenceEditPlugin extends EMFPlugin {
     /**
      * Returns the singleton instance of the Eclipse plugin. <!-- begin-user-doc
      * --> <!-- end-user-doc -->
-     * 
+     *
      * @return the singleton instance.
      * @generated
      */
@@ -64,7 +64,7 @@ public final class PropertiesextwidgetsreferenceEditPlugin extends EMFPlugin {
     /**
      * Returns the singleton instance of the Eclipse plugin. <!-- begin-user-doc
      * --> <!-- end-user-doc -->
-     * 
+     *
      * @return the singleton instance.
      * @generated
      */
@@ -81,7 +81,7 @@ public final class PropertiesextwidgetsreferenceEditPlugin extends EMFPlugin {
     public static class Implementation extends EclipsePlugin {
         /**
          * Creates an instance. <!-- begin-user-doc --> <!-- end-user-doc -->
-         * 
+         *
          * @generated
          */
         public Implementation() {
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.ecore b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.ecore
index 44da1941e1..8cc2207aca 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.ecore
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.ecore
@@ -7,5 +7,15 @@
         lowerBound="1" eType="ecore:EDataType ../../org.eclipse.sirius/model/viewpoint.ecore#//description/InterpretedExpression"/>
     <eStructuralFeatures xsi:type="ecore:EAttribute" name="referenceOwnerExpression"
         eType="ecore:EDataType ../../org.eclipse.sirius/model/viewpoint.ecore#//description/InterpretedExpression"/>
+    <eStructuralFeatures xsi:type="ecore:EReference" name="style" eType="#//ExtReferenceWidgetStyle"
+        containment="true"/>
+    <eStructuralFeatures xsi:type="ecore:EReference" name="conditionalStyles" upperBound="-1"
+        eType="#//ExtReferenceWidgetConditionalStyle" containment="true"/>
+  </eClassifiers>
+  <eClassifiers xsi:type="ecore:EClass" name="ExtReferenceWidgetStyle" eSuperTypes="../../org.eclipse.sirius.properties/model/properties.ecore#//WidgetStyle"/>
+  <eClassifiers xsi:type="ecore:EClass" name="ExtReferenceWidgetConditionalStyle"
+      eSuperTypes="../../org.eclipse.sirius.properties/model/properties.ecore#//WidgetConditionalStyle">
+    <eStructuralFeatures xsi:type="ecore:EReference" name="style" eType="#//ExtReferenceWidgetStyle"
+        containment="true"/>
   </eClassifiers>
 </ecore:EPackage>
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.genmodel b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.genmodel
index 03391442b0..184aae093d 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.genmodel
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/model/properties-ext-widgets-reference.genmodel
@@ -14,7 +14,14 @@
       disposableProviderFactory="true" extensibleProviderFactory="true" childCreationExtenders="true"
       ecorePackage="properties-ext-widgets-reference.ecore#/">
     <genClasses ecoreClass="properties-ext-widgets-reference.ecore#//ExtReferenceDescription">
-      <genFeatures createChild="false" ecoreFeature="ecore:EAttribute properties-ext-widgets-reference.ecore#//ExtReferenceDescription/referenceName"/>
+      <genFeatures createChild="false" ecoreFeature="ecore:EAttribute properties-ext-widgets-reference.ecore#//ExtReferenceDescription/referenceNameExpression"/>
+      <genFeatures createChild="false" ecoreFeature="ecore:EAttribute properties-ext-widgets-reference.ecore#//ExtReferenceDescription/referenceOwnerExpression"/>
+      <genFeatures property="None" children="true" createChild="true" ecoreFeature="ecore:EReference properties-ext-widgets-reference.ecore#//ExtReferenceDescription/style"/>
+      <genFeatures property="None" children="true" createChild="true" ecoreFeature="ecore:EReference properties-ext-widgets-reference.ecore#//ExtReferenceDescription/conditionalStyles"/>
+    </genClasses>
+    <genClasses ecoreClass="properties-ext-widgets-reference.ecore#//ExtReferenceWidgetStyle"/>
+    <genClasses ecoreClass="properties-ext-widgets-reference.ecore#//ExtReferenceWidgetConditionalStyle">
+      <genFeatures property="None" children="true" createChild="true" ecoreFeature="ecore:EReference properties-ext-widgets-reference.ecore#//ExtReferenceWidgetConditionalStyle/style"/>
     </genClasses>
   </genPackages>
 </genmodel:GenModel>
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceDescription.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceDescription.java
index 6d2abe7e28..2af5fc9a2b 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceDescription.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceDescription.java
@@ -11,6 +11,7 @@
  */
 package org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference;
 
+import org.eclipse.emf.common.util.EList;
 import org.eclipse.sirius.properties.WidgetDescription;
 
 /**
@@ -19,6 +20,7 @@ import org.eclipse.sirius.properties.WidgetDescription;
  *
  * <p>
  * The following features are supported:
+ * </p>
  * <ul>
  * <li>
  * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getReferenceNameExpression
@@ -26,8 +28,13 @@ import org.eclipse.sirius.properties.WidgetDescription;
  * <li>
  * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getReferenceOwnerExpression
  * <em>Reference Owner Expression</em>}</li>
+ * <li>
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getStyle
+ * <em>Style</em>}</li>
+ * <li>
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getConditionalStyles
+ * <em>Conditional Styles</em>}</li>
  * </ul>
- * </p>
  *
  * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage#getExtReferenceDescription()
  * @model
@@ -99,4 +106,53 @@ public interface ExtReferenceDescription extends WidgetDescription {
      */
     void setReferenceOwnerExpression(String value);
 
+    /**
+     * Returns the value of the '<em><b>Style</b></em>' containment reference.
+     * <!-- begin-user-doc -->
+     * <p>
+     * If the meaning of the '<em>Style</em>' containment reference isn't clear,
+     * there really should be more of a description here...
+     * </p>
+     * <!-- end-user-doc -->
+     *
+     * @return the value of the '<em>Style</em>' containment reference.
+     * @see #setStyle(ExtReferenceWidgetStyle)
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage#getExtReferenceDescription_Style()
+     * @model containment="true"
+     * @generated
+     */
+    ExtReferenceWidgetStyle getStyle();
+
+    /**
+     * Sets the value of the '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getStyle
+     * <em>Style</em>}' containment reference. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @param value
+     *            the new value of the '<em>Style</em>' containment reference.
+     * @see #getStyle()
+     * @generated
+     */
+    void setStyle(ExtReferenceWidgetStyle value);
+
+    /**
+     * Returns the value of the '<em><b>Conditional Styles</b></em>' containment
+     * reference list. The list contents are of type
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle}
+     * . <!-- begin-user-doc -->
+     * <p>
+     * If the meaning of the '<em>Conditional Styles</em>' containment reference
+     * list isn't clear, there really should be more of a description here...
+     * </p>
+     * <!-- end-user-doc -->
+     *
+     * @return the value of the '<em>Conditional Styles</em>' containment
+     *         reference list.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage#getExtReferenceDescription_ConditionalStyles()
+     * @model containment="true"
+     * @generated
+     */
+    EList<ExtReferenceWidgetConditionalStyle> getConditionalStyles();
+
 } // ExtReferenceDescription
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceWidgetConditionalStyle.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceWidgetConditionalStyle.java
new file mode 100644
index 0000000000..ae8e3e4848
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceWidgetConditionalStyle.java
@@ -0,0 +1,65 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.properties.ext.widgets.reference.propertiesextwidgetsreference;
+
+import org.eclipse.sirius.properties.WidgetConditionalStyle;
+
+/**
+ * <!-- begin-user-doc --> A representation of the model object '
+ * <em><b>Ext Reference Widget Conditional Style</b></em>'. <!-- end-user-doc
+ * -->
+ *
+ * <p>
+ * The following features are supported:
+ * <ul>
+ * <li>
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle#getStyle
+ * <em>Style</em>}</li>
+ * </ul>
+ * </p>
+ *
+ * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage#getExtReferenceWidgetConditionalStyle()
+ * @model
+ * @generated
+ */
+public interface ExtReferenceWidgetConditionalStyle extends WidgetConditionalStyle {
+    /**
+     * Returns the value of the '<em><b>Style</b></em>' containment reference.
+     * <!-- begin-user-doc -->
+     * <p>
+     * If the meaning of the '<em>Style</em>' containment reference isn't clear,
+     * there really should be more of a description here...
+     * </p>
+     * <!-- end-user-doc -->
+     *
+     * @return the value of the '<em>Style</em>' containment reference.
+     * @see #setStyle(ExtReferenceWidgetStyle)
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage#getExtReferenceWidgetConditionalStyle_Style()
+     * @model containment="true"
+     * @generated
+     */
+    ExtReferenceWidgetStyle getStyle();
+
+    /**
+     * Sets the value of the '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle#getStyle
+     * <em>Style</em>}' containment reference. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @param value
+     *            the new value of the '<em>Style</em>' containment reference.
+     * @see #getStyle()
+     * @generated
+     */
+    void setStyle(ExtReferenceWidgetStyle value);
+
+} // ExtReferenceWidgetConditionalStyle
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceWidgetStyle.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceWidgetStyle.java
new file mode 100644
index 0000000000..7c4b03197f
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/ExtReferenceWidgetStyle.java
@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.properties.ext.widgets.reference.propertiesextwidgetsreference;
+
+import org.eclipse.sirius.properties.WidgetStyle;
+
+/**
+ * <!-- begin-user-doc --> A representation of the model object '
+ * <em><b>Ext Reference Widget Style</b></em>'. <!-- end-user-doc -->
+ *
+ *
+ * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage#getExtReferenceWidgetStyle()
+ * @model
+ * @generated
+ */
+public interface ExtReferenceWidgetStyle extends WidgetStyle {
+} // ExtReferenceWidgetStyle
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferenceFactory.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferenceFactory.java
index 757325b01f..b663af58c2 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferenceFactory.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferenceFactory.java
@@ -39,6 +39,26 @@ public interface PropertiesExtWidgetsReferenceFactory extends EFactory {
     ExtReferenceDescription createExtReferenceDescription();
 
     /**
+     * Returns a new object of class '<em>Ext Reference Widget Style</em>'. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @return a new object of class '<em>Ext Reference Widget Style</em>'.
+     * @generated
+     */
+    ExtReferenceWidgetStyle createExtReferenceWidgetStyle();
+
+    /**
+     * Returns a new object of class '
+     * <em>Ext Reference Widget Conditional Style</em>'. <!-- begin-user-doc -->
+     * <!-- end-user-doc -->
+     *
+     * @return a new object of class '
+     *         <em>Ext Reference Widget Conditional Style</em>'.
+     * @generated
+     */
+    ExtReferenceWidgetConditionalStyle createExtReferenceWidgetConditionalStyle();
+
+    /**
      * Returns the package supported by this factory. <!-- begin-user-doc -->
      * <!-- end-user-doc -->
      *
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferencePackage.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferencePackage.java
index 23d1cd43b1..420308640c 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferencePackage.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/PropertiesExtWidgetsReferencePackage.java
@@ -14,6 +14,7 @@ package org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgets
 import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EPackage;
+import org.eclipse.emf.ecore.EReference;
 import org.eclipse.sirius.properties.PropertiesPackage;
 
 /**
@@ -129,6 +130,24 @@ public interface PropertiesExtWidgetsReferencePackage extends EPackage {
     int EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION = PropertiesPackage.WIDGET_DESCRIPTION_FEATURE_COUNT + 1;
 
     /**
+     * The feature id for the '<em><b>Style</b></em>' containment reference.
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_DESCRIPTION__STYLE = PropertiesPackage.WIDGET_DESCRIPTION_FEATURE_COUNT + 2;
+
+    /**
+     * The feature id for the '<em><b>Conditional Styles</b></em>' containment
+     * reference list. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES = PropertiesPackage.WIDGET_DESCRIPTION_FEATURE_COUNT + 3;
+
+    /**
      * The number of structural features of the '
      * <em>Ext Reference Description</em>' class. <!-- begin-user-doc --> <!--
      * end-user-doc -->
@@ -136,7 +155,114 @@ public interface PropertiesExtWidgetsReferencePackage extends EPackage {
      * @generated
      * @ordered
      */
-    int EXT_REFERENCE_DESCRIPTION_FEATURE_COUNT = PropertiesPackage.WIDGET_DESCRIPTION_FEATURE_COUNT + 2;
+    int EXT_REFERENCE_DESCRIPTION_FEATURE_COUNT = PropertiesPackage.WIDGET_DESCRIPTION_FEATURE_COUNT + 4;
+
+    /**
+     * The meta object id for the '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetStyleImpl
+     * <em>Ext Reference Widget Style</em>}' class. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetStyleImpl
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.PropertiesExtWidgetsReferencePackageImpl#getExtReferenceWidgetStyle()
+     * @generated
+     */
+    int EXT_REFERENCE_WIDGET_STYLE = 1;
+
+    /**
+     * The feature id for the '<em><b>Label Font Name Expression</b></em>'
+     * attribute. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_STYLE__LABEL_FONT_NAME_EXPRESSION = PropertiesPackage.WIDGET_STYLE__LABEL_FONT_NAME_EXPRESSION;
+
+    /**
+     * The feature id for the '<em><b>Label Font Size Expression</b></em>'
+     * attribute. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_STYLE__LABEL_FONT_SIZE_EXPRESSION = PropertiesPackage.WIDGET_STYLE__LABEL_FONT_SIZE_EXPRESSION;
+
+    /**
+     * The feature id for the '<em><b>Label Background Color</b></em>'
+     * reference. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_STYLE__LABEL_BACKGROUND_COLOR = PropertiesPackage.WIDGET_STYLE__LABEL_BACKGROUND_COLOR;
+
+    /**
+     * The feature id for the '<em><b>Label Foreground Color</b></em>'
+     * reference. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_STYLE__LABEL_FOREGROUND_COLOR = PropertiesPackage.WIDGET_STYLE__LABEL_FOREGROUND_COLOR;
+
+    /**
+     * The feature id for the '<em><b>Label Font Format</b></em>' attribute
+     * list. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_STYLE__LABEL_FONT_FORMAT = PropertiesPackage.WIDGET_STYLE__LABEL_FONT_FORMAT;
+
+    /**
+     * The number of structural features of the '
+     * <em>Ext Reference Widget Style</em>' class. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_STYLE_FEATURE_COUNT = PropertiesPackage.WIDGET_STYLE_FEATURE_COUNT + 0;
+
+    /**
+     * The meta object id for the '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetConditionalStyleImpl
+     * <em>Ext Reference Widget Conditional Style</em>}' class. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetConditionalStyleImpl
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.PropertiesExtWidgetsReferencePackageImpl#getExtReferenceWidgetConditionalStyle()
+     * @generated
+     */
+    int EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE = 2;
+
+    /**
+     * The feature id for the '<em><b>Precondition Expression</b></em>'
+     * attribute. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__PRECONDITION_EXPRESSION = PropertiesPackage.WIDGET_CONDITIONAL_STYLE__PRECONDITION_EXPRESSION;
+
+    /**
+     * The feature id for the '<em><b>Style</b></em>' containment reference.
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE = PropertiesPackage.WIDGET_CONDITIONAL_STYLE_FEATURE_COUNT + 0;
+
+    /**
+     * The number of structural features of the '
+     * <em>Ext Reference Widget Conditional Style</em>' class. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     * @ordered
+     */
+    int EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE_FEATURE_COUNT = PropertiesPackage.WIDGET_CONDITIONAL_STYLE_FEATURE_COUNT + 1;
 
     /**
      * Returns the meta object for class '
@@ -179,6 +305,69 @@ public interface PropertiesExtWidgetsReferencePackage extends EPackage {
     EAttribute getExtReferenceDescription_ReferenceOwnerExpression();
 
     /**
+     * Returns the meta object for the containment reference '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getStyle
+     * <em>Style</em>}'. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @return the meta object for the containment reference '<em>Style</em>'.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getStyle()
+     * @see #getExtReferenceDescription()
+     * @generated
+     */
+    EReference getExtReferenceDescription_Style();
+
+    /**
+     * Returns the meta object for the containment reference list '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getConditionalStyles
+     * <em>Conditional Styles</em>}'. <!-- begin-user-doc --> <!-- end-user-doc
+     * -->
+     *
+     * @return the meta object for the containment reference list '
+     *         <em>Conditional Styles</em>'.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription#getConditionalStyles()
+     * @see #getExtReferenceDescription()
+     * @generated
+     */
+    EReference getExtReferenceDescription_ConditionalStyles();
+
+    /**
+     * Returns the meta object for class '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle
+     * <em>Ext Reference Widget Style</em>}'. <!-- begin-user-doc --> <!--
+     * end-user-doc -->
+     *
+     * @return the meta object for class '<em>Ext Reference Widget Style</em>'.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle
+     * @generated
+     */
+    EClass getExtReferenceWidgetStyle();
+
+    /**
+     * Returns the meta object for class '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle
+     * <em>Ext Reference Widget Conditional Style</em>}'. <!-- begin-user-doc
+     * --> <!-- end-user-doc -->
+     *
+     * @return the meta object for class '
+     *         <em>Ext Reference Widget Conditional Style</em>'.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle
+     * @generated
+     */
+    EClass getExtReferenceWidgetConditionalStyle();
+
+    /**
+     * Returns the meta object for the containment reference '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle#getStyle
+     * <em>Style</em>}'. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @return the meta object for the containment reference '<em>Style</em>'.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle#getStyle()
+     * @see #getExtReferenceWidgetConditionalStyle()
+     * @generated
+     */
+    EReference getExtReferenceWidgetConditionalStyle_Style();
+
+    /**
      * Returns the factory that creates the instances of the model. <!--
      * begin-user-doc --> <!-- end-user-doc -->
      *
@@ -232,6 +421,55 @@ public interface PropertiesExtWidgetsReferencePackage extends EPackage {
          */
         EAttribute EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION = PropertiesExtWidgetsReferencePackage.eINSTANCE.getExtReferenceDescription_ReferenceOwnerExpression();
 
+        /**
+         * The meta object literal for the '<em><b>Style</b></em>' containment
+         * reference feature. <!-- begin-user-doc --> <!-- end-user-doc -->
+         *
+         * @generated
+         */
+        EReference EXT_REFERENCE_DESCRIPTION__STYLE = PropertiesExtWidgetsReferencePackage.eINSTANCE.getExtReferenceDescription_Style();
+
+        /**
+         * The meta object literal for the '<em><b>Conditional Styles</b></em>'
+         * containment reference list feature. <!-- begin-user-doc --> <!--
+         * end-user-doc -->
+         *
+         * @generated
+         */
+        EReference EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES = PropertiesExtWidgetsReferencePackage.eINSTANCE.getExtReferenceDescription_ConditionalStyles();
+
+        /**
+         * The meta object literal for the '
+         * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetStyleImpl
+         * <em>Ext Reference Widget Style</em>}' class. <!-- begin-user-doc -->
+         * <!-- end-user-doc -->
+         *
+         * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetStyleImpl
+         * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.PropertiesExtWidgetsReferencePackageImpl#getExtReferenceWidgetStyle()
+         * @generated
+         */
+        EClass EXT_REFERENCE_WIDGET_STYLE = PropertiesExtWidgetsReferencePackage.eINSTANCE.getExtReferenceWidgetStyle();
+
+        /**
+         * The meta object literal for the '
+         * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetConditionalStyleImpl
+         * <em>Ext Reference Widget Conditional Style</em>}' class. <!--
+         * begin-user-doc --> <!-- end-user-doc -->
+         *
+         * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetConditionalStyleImpl
+         * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.PropertiesExtWidgetsReferencePackageImpl#getExtReferenceWidgetConditionalStyle()
+         * @generated
+         */
+        EClass EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE = PropertiesExtWidgetsReferencePackage.eINSTANCE.getExtReferenceWidgetConditionalStyle();
+
+        /**
+         * The meta object literal for the '<em><b>Style</b></em>' containment
+         * reference feature. <!-- begin-user-doc --> <!-- end-user-doc -->
+         *
+         * @generated
+         */
+        EReference EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE = PropertiesExtWidgetsReferencePackage.eINSTANCE.getExtReferenceWidgetConditionalStyle_Style();
+
     }
 
 } // PropertiesExtWidgetsReferencePackage
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceDescriptionImpl.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceDescriptionImpl.java
index e7511406dd..4dbcebd212 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceDescriptionImpl.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceDescriptionImpl.java
@@ -11,10 +11,19 @@
  */
 package org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl;
 
+import java.util.Collection;
+
 import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.common.notify.NotificationChain;
+import org.eclipse.emf.common.util.EList;
 import org.eclipse.emf.ecore.EClass;
+import org.eclipse.emf.ecore.InternalEObject;
 import org.eclipse.emf.ecore.impl.ENotificationImpl;
+import org.eclipse.emf.ecore.util.EObjectContainmentEList;
+import org.eclipse.emf.ecore.util.InternalEList;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
 import org.eclipse.sirius.properties.impl.WidgetDescriptionImpl;
 
@@ -23,6 +32,7 @@ import org.eclipse.sirius.properties.impl.WidgetDescriptionImpl;
  * <em><b>Ext Reference Description</b></em>'. <!-- end-user-doc -->
  * <p>
  * The following features are implemented:
+ * </p>
  * <ul>
  * <li>
  * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceDescriptionImpl#getReferenceNameExpression
@@ -30,8 +40,13 @@ import org.eclipse.sirius.properties.impl.WidgetDescriptionImpl;
  * <li>
  * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceDescriptionImpl#getReferenceOwnerExpression
  * <em>Reference Owner Expression</em>}</li>
+ * <li>
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceDescriptionImpl#getStyle
+ * <em>Style</em>}</li>
+ * <li>
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceDescriptionImpl#getConditionalStyles
+ * <em>Conditional Styles</em>}</li>
  * </ul>
- * </p>
  *
  * @generated
  */
@@ -81,6 +96,27 @@ public class ExtReferenceDescriptionImpl extends WidgetDescriptionImpl implement
     protected String referenceOwnerExpression = ExtReferenceDescriptionImpl.REFERENCE_OWNER_EXPRESSION_EDEFAULT;
 
     /**
+     * The cached value of the '{@link #getStyle() <em>Style</em>}' containment
+     * reference. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @see #getStyle()
+     * @generated
+     * @ordered
+     */
+    protected ExtReferenceWidgetStyle style;
+
+    /**
+     * The cached value of the '{@link #getConditionalStyles()
+     * <em>Conditional Styles</em>}' containment reference list. <!--
+     * begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @see #getConditionalStyles()
+     * @generated
+     * @ordered
+     */
+    protected EList<ExtReferenceWidgetConditionalStyle> conditionalStyles;
+
+    /**
      * <!-- begin-user-doc --> <!-- end-user-doc -->
      *
      * @generated
@@ -155,12 +191,99 @@ public class ExtReferenceDescriptionImpl extends WidgetDescriptionImpl implement
      * @generated
      */
     @Override
+    public ExtReferenceWidgetStyle getStyle() {
+        return style;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    public NotificationChain basicSetStyle(ExtReferenceWidgetStyle newStyle, NotificationChain msgs) {
+        ExtReferenceWidgetStyle oldStyle = style;
+        style = newStyle;
+        if (eNotificationRequired()) {
+            ENotificationImpl notification = new ENotificationImpl(this, Notification.SET, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE, oldStyle, newStyle);
+            if (msgs == null) {
+                msgs = notification;
+            } else {
+                msgs.add(notification);
+            }
+        }
+        return msgs;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public void setStyle(ExtReferenceWidgetStyle newStyle) {
+        if (newStyle != style) {
+            NotificationChain msgs = null;
+            if (style != null) {
+                msgs = ((InternalEObject) style).eInverseRemove(this, InternalEObject.EOPPOSITE_FEATURE_BASE - PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE, null, msgs);
+            }
+            if (newStyle != null) {
+                msgs = ((InternalEObject) newStyle).eInverseAdd(this, InternalEObject.EOPPOSITE_FEATURE_BASE - PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE, null, msgs);
+            }
+            msgs = basicSetStyle(newStyle, msgs);
+            if (msgs != null) {
+                msgs.dispatch();
+            }
+        } else if (eNotificationRequired()) {
+            eNotify(new ENotificationImpl(this, Notification.SET, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE, newStyle, newStyle));
+        }
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public EList<ExtReferenceWidgetConditionalStyle> getConditionalStyles() {
+        if (conditionalStyles == null) {
+            conditionalStyles = new EObjectContainmentEList<ExtReferenceWidgetConditionalStyle>(ExtReferenceWidgetConditionalStyle.class, this,
+                    PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES);
+        }
+        return conditionalStyles;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public NotificationChain eInverseRemove(InternalEObject otherEnd, int featureID, NotificationChain msgs) {
+        switch (featureID) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE:
+            return basicSetStyle(null, msgs);
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES:
+            return ((InternalEList<?>) getConditionalStyles()).basicRemove(otherEnd, msgs);
+        }
+        return super.eInverseRemove(otherEnd, featureID, msgs);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
     public Object eGet(int featureID, boolean resolve, boolean coreType) {
         switch (featureID) {
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_NAME_EXPRESSION:
             return getReferenceNameExpression();
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION:
             return getReferenceOwnerExpression();
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE:
+            return getStyle();
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES:
+            return getConditionalStyles();
         }
         return super.eGet(featureID, resolve, coreType);
     }
@@ -170,6 +293,7 @@ public class ExtReferenceDescriptionImpl extends WidgetDescriptionImpl implement
      *
      * @generated
      */
+    @SuppressWarnings("unchecked")
     @Override
     public void eSet(int featureID, Object newValue) {
         switch (featureID) {
@@ -179,6 +303,13 @@ public class ExtReferenceDescriptionImpl extends WidgetDescriptionImpl implement
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION:
             setReferenceOwnerExpression((String) newValue);
             return;
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE:
+            setStyle((ExtReferenceWidgetStyle) newValue);
+            return;
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES:
+            getConditionalStyles().clear();
+            getConditionalStyles().addAll((Collection<? extends ExtReferenceWidgetConditionalStyle>) newValue);
+            return;
         }
         super.eSet(featureID, newValue);
     }
@@ -197,6 +328,12 @@ public class ExtReferenceDescriptionImpl extends WidgetDescriptionImpl implement
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION:
             setReferenceOwnerExpression(ExtReferenceDescriptionImpl.REFERENCE_OWNER_EXPRESSION_EDEFAULT);
             return;
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE:
+            setStyle((ExtReferenceWidgetStyle) null);
+            return;
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES:
+            getConditionalStyles().clear();
+            return;
         }
         super.eUnset(featureID);
     }
@@ -210,11 +347,15 @@ public class ExtReferenceDescriptionImpl extends WidgetDescriptionImpl implement
     public boolean eIsSet(int featureID) {
         switch (featureID) {
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_NAME_EXPRESSION:
-            return ExtReferenceDescriptionImpl.REFERENCE_NAME_EXPRESSION_EDEFAULT == null ? referenceNameExpression != null : !ExtReferenceDescriptionImpl.REFERENCE_NAME_EXPRESSION_EDEFAULT
-            .equals(referenceNameExpression);
+            return ExtReferenceDescriptionImpl.REFERENCE_NAME_EXPRESSION_EDEFAULT == null ? referenceNameExpression != null
+                    : !ExtReferenceDescriptionImpl.REFERENCE_NAME_EXPRESSION_EDEFAULT.equals(referenceNameExpression);
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION:
-            return ExtReferenceDescriptionImpl.REFERENCE_OWNER_EXPRESSION_EDEFAULT == null ? referenceOwnerExpression != null : !ExtReferenceDescriptionImpl.REFERENCE_OWNER_EXPRESSION_EDEFAULT
-            .equals(referenceOwnerExpression);
+            return ExtReferenceDescriptionImpl.REFERENCE_OWNER_EXPRESSION_EDEFAULT == null ? referenceOwnerExpression != null
+                    : !ExtReferenceDescriptionImpl.REFERENCE_OWNER_EXPRESSION_EDEFAULT.equals(referenceOwnerExpression);
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE:
+            return style != null;
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES:
+            return conditionalStyles != null && !conditionalStyles.isEmpty();
         }
         return super.eIsSet(featureID);
     }
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceWidgetConditionalStyleImpl.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceWidgetConditionalStyleImpl.java
new file mode 100644
index 0000000000..61825c35e0
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceWidgetConditionalStyleImpl.java
@@ -0,0 +1,196 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.properties.ext.widgets.reference.propertiesextwidgetsreference.impl;
+
+import org.eclipse.emf.common.notify.Notification;
+import org.eclipse.emf.common.notify.NotificationChain;
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.emf.ecore.InternalEObject;
+import org.eclipse.emf.ecore.impl.ENotificationImpl;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
+import org.eclipse.sirius.properties.impl.WidgetConditionalStyleImpl;
+
+/**
+ * <!-- begin-user-doc --> An implementation of the model object '
+ * <em><b>Ext Reference Widget Conditional Style</b></em>'. <!-- end-user-doc
+ * -->
+ * <p>
+ * The following features are implemented:
+ * <ul>
+ * <li>
+ * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.impl.ExtReferenceWidgetConditionalStyleImpl#getStyle
+ * <em>Style</em>}</li>
+ * </ul>
+ * </p>
+ *
+ * @generated
+ */
+public class ExtReferenceWidgetConditionalStyleImpl extends WidgetConditionalStyleImpl implements ExtReferenceWidgetConditionalStyle {
+    /**
+     * The cached value of the '{@link #getStyle() <em>Style</em>}' containment
+     * reference. <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @see #getStyle()
+     * @generated
+     * @ordered
+     */
+    protected ExtReferenceWidgetStyle style;
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    protected ExtReferenceWidgetConditionalStyleImpl() {
+        super();
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    protected EClass eStaticClass() {
+        return PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public ExtReferenceWidgetStyle getStyle() {
+        return style;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    public NotificationChain basicSetStyle(ExtReferenceWidgetStyle newStyle, NotificationChain msgs) {
+        ExtReferenceWidgetStyle oldStyle = style;
+        style = newStyle;
+        if (eNotificationRequired()) {
+            ENotificationImpl notification = new ENotificationImpl(this, Notification.SET, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE, oldStyle, newStyle);
+            if (msgs == null) {
+                msgs = notification;
+            } else {
+                msgs.add(notification);
+            }
+        }
+        return msgs;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public void setStyle(ExtReferenceWidgetStyle newStyle) {
+        if (newStyle != style) {
+            NotificationChain msgs = null;
+            if (style != null) {
+                msgs = ((InternalEObject) style).eInverseRemove(this, InternalEObject.EOPPOSITE_FEATURE_BASE - PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE, null,
+                        msgs);
+            }
+            if (newStyle != null) {
+                msgs = ((InternalEObject) newStyle).eInverseAdd(this, InternalEObject.EOPPOSITE_FEATURE_BASE - PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE, null,
+                        msgs);
+            }
+            msgs = basicSetStyle(newStyle, msgs);
+            if (msgs != null) {
+                msgs.dispatch();
+            }
+        } else if (eNotificationRequired()) {
+            eNotify(new ENotificationImpl(this, Notification.SET, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE, newStyle, newStyle));
+        }
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public NotificationChain eInverseRemove(InternalEObject otherEnd, int featureID, NotificationChain msgs) {
+        switch (featureID) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE:
+            return basicSetStyle(null, msgs);
+        }
+        return super.eInverseRemove(otherEnd, featureID, msgs);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public Object eGet(int featureID, boolean resolve, boolean coreType) {
+        switch (featureID) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE:
+            return getStyle();
+        }
+        return super.eGet(featureID, resolve, coreType);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public void eSet(int featureID, Object newValue) {
+        switch (featureID) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE:
+            setStyle((ExtReferenceWidgetStyle) newValue);
+            return;
+        }
+        super.eSet(featureID, newValue);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public void eUnset(int featureID) {
+        switch (featureID) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE:
+            setStyle((ExtReferenceWidgetStyle) null);
+            return;
+        }
+        super.eUnset(featureID);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public boolean eIsSet(int featureID) {
+        switch (featureID) {
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE:
+            return style != null;
+        }
+        return super.eIsSet(featureID);
+    }
+
+} // ExtReferenceWidgetConditionalStyleImpl
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceWidgetStyleImpl.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceWidgetStyleImpl.java
new file mode 100644
index 0000000000..328cb413b6
--- /dev/null
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/ExtReferenceWidgetStyleImpl.java
@@ -0,0 +1,45 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.properties.ext.widgets.reference.propertiesextwidgetsreference.impl;
+
+import org.eclipse.emf.ecore.EClass;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
+import org.eclipse.sirius.properties.impl.WidgetStyleImpl;
+
+/**
+ * <!-- begin-user-doc --> An implementation of the model object '
+ * <em><b>Ext Reference Widget Style</b></em>'. <!-- end-user-doc -->
+ *
+ * @generated
+ */
+public class ExtReferenceWidgetStyleImpl extends WidgetStyleImpl implements ExtReferenceWidgetStyle {
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    protected ExtReferenceWidgetStyleImpl() {
+        super();
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    protected EClass eStaticClass() {
+        return PropertiesExtWidgetsReferencePackage.Literals.EXT_REFERENCE_WIDGET_STYLE;
+    }
+
+} // ExtReferenceWidgetStyleImpl
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferenceFactoryImpl.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferenceFactoryImpl.java
index 2cee4a33d6..098124c14c 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferenceFactoryImpl.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferenceFactoryImpl.java
@@ -17,6 +17,8 @@ import org.eclipse.emf.ecore.EPackage;
 import org.eclipse.emf.ecore.impl.EFactoryImpl;
 import org.eclipse.emf.ecore.plugin.EcorePlugin;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferenceFactory;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
 
@@ -66,6 +68,10 @@ public class PropertiesExtWidgetsReferenceFactoryImpl extends EFactoryImpl imple
         switch (eClass.getClassifierID()) {
         case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION:
             return createExtReferenceDescription();
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_STYLE:
+            return createExtReferenceWidgetStyle();
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE:
+            return createExtReferenceWidgetConditionalStyle();
         default:
             throw new IllegalArgumentException("The class '" + eClass.getName() + "' is not a valid classifier"); //$NON-NLS-1$ //$NON-NLS-2$
         }
@@ -88,6 +94,28 @@ public class PropertiesExtWidgetsReferenceFactoryImpl extends EFactoryImpl imple
      * @generated
      */
     @Override
+    public ExtReferenceWidgetStyle createExtReferenceWidgetStyle() {
+        ExtReferenceWidgetStyleImpl extReferenceWidgetStyle = new ExtReferenceWidgetStyleImpl();
+        return extReferenceWidgetStyle;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public ExtReferenceWidgetConditionalStyle createExtReferenceWidgetConditionalStyle() {
+        ExtReferenceWidgetConditionalStyleImpl extReferenceWidgetConditionalStyle = new ExtReferenceWidgetConditionalStyleImpl();
+        return extReferenceWidgetConditionalStyle;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
     public PropertiesExtWidgetsReferencePackage getPropertiesExtWidgetsReferencePackage() {
         return (PropertiesExtWidgetsReferencePackage) getEPackage();
     }
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferencePackageImpl.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferencePackageImpl.java
index 31b182e672..30dac5de4e 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferencePackageImpl.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/impl/PropertiesExtWidgetsReferencePackageImpl.java
@@ -14,9 +14,12 @@ package org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgets
 import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EPackage;
+import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.impl.EPackageImpl;
 import org.eclipse.sirius.properties.PropertiesPackage;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferenceFactory;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
 import org.eclipse.sirius.viewpoint.description.DescriptionPackage;
@@ -36,6 +39,20 @@ public class PropertiesExtWidgetsReferencePackageImpl extends EPackageImpl imple
     private EClass extReferenceDescriptionEClass = null;
 
     /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    private EClass extReferenceWidgetStyleEClass = null;
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    private EClass extReferenceWidgetConditionalStyleEClass = null;
+
+    /**
      * Creates an instance of the model <b>Package</b>, registered with
      * {@link org.eclipse.emf.ecore.EPackage.Registry EPackage.Registry} by the
      * package package URI value.
@@ -142,6 +159,56 @@ public class PropertiesExtWidgetsReferencePackageImpl extends EPackageImpl imple
      * @generated
      */
     @Override
+    public EReference getExtReferenceDescription_Style() {
+        return (EReference) extReferenceDescriptionEClass.getEStructuralFeatures().get(2);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public EReference getExtReferenceDescription_ConditionalStyles() {
+        return (EReference) extReferenceDescriptionEClass.getEStructuralFeatures().get(3);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public EClass getExtReferenceWidgetStyle() {
+        return extReferenceWidgetStyleEClass;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public EClass getExtReferenceWidgetConditionalStyle() {
+        return extReferenceWidgetConditionalStyleEClass;
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
+    public EReference getExtReferenceWidgetConditionalStyle_Style() {
+        return (EReference) extReferenceWidgetConditionalStyleEClass.getEStructuralFeatures().get(0);
+    }
+
+    /**
+     * <!-- begin-user-doc --> <!-- end-user-doc -->
+     *
+     * @generated
+     */
+    @Override
     public PropertiesExtWidgetsReferenceFactory getPropertiesExtWidgetsReferenceFactory() {
         return (PropertiesExtWidgetsReferenceFactory) getEFactoryInstance();
     }
@@ -170,6 +237,13 @@ public class PropertiesExtWidgetsReferencePackageImpl extends EPackageImpl imple
         extReferenceDescriptionEClass = createEClass(PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION);
         createEAttribute(extReferenceDescriptionEClass, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_NAME_EXPRESSION);
         createEAttribute(extReferenceDescriptionEClass, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__REFERENCE_OWNER_EXPRESSION);
+        createEReference(extReferenceDescriptionEClass, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__STYLE);
+        createEReference(extReferenceDescriptionEClass, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_DESCRIPTION__CONDITIONAL_STYLES);
+
+        extReferenceWidgetStyleEClass = createEClass(PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_STYLE);
+
+        extReferenceWidgetConditionalStyleEClass = createEClass(PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE);
+        createEReference(extReferenceWidgetConditionalStyleEClass, PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE__STYLE);
     }
 
     /**
@@ -207,18 +281,33 @@ public class PropertiesExtWidgetsReferencePackageImpl extends EPackageImpl imple
 
         // Add supertypes to classes
         extReferenceDescriptionEClass.getESuperTypes().add(thePropertiesPackage.getWidgetDescription());
+        extReferenceWidgetStyleEClass.getESuperTypes().add(thePropertiesPackage.getWidgetStyle());
+        extReferenceWidgetConditionalStyleEClass.getESuperTypes().add(thePropertiesPackage.getWidgetConditionalStyle());
 
         // Initialize classes and features; add operations and parameters
-        initEClass(extReferenceDescriptionEClass, ExtReferenceDescription.class,
-                "ExtReferenceDescription", !EPackageImpl.IS_ABSTRACT, !EPackageImpl.IS_INTERFACE, EPackageImpl.IS_GENERATED_INSTANCE_CLASS); //$NON-NLS-1$
-        initEAttribute(
-                getExtReferenceDescription_ReferenceNameExpression(),
-                theDescriptionPackage.getInterpretedExpression(),
-                "referenceNameExpression", null, 1, 1, ExtReferenceDescription.class, !EPackageImpl.IS_TRANSIENT, !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, !EPackageImpl.IS_UNSETTABLE, !EPackageImpl.IS_ID, EPackageImpl.IS_UNIQUE, !EPackageImpl.IS_DERIVED, EPackageImpl.IS_ORDERED); //$NON-NLS-1$
-        initEAttribute(
-                getExtReferenceDescription_ReferenceOwnerExpression(),
-                theDescriptionPackage.getInterpretedExpression(),
-                "referenceOwnerExpression", null, 0, 1, ExtReferenceDescription.class, !EPackageImpl.IS_TRANSIENT, !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, !EPackageImpl.IS_UNSETTABLE, !EPackageImpl.IS_ID, EPackageImpl.IS_UNIQUE, !EPackageImpl.IS_DERIVED, EPackageImpl.IS_ORDERED); //$NON-NLS-1$
+        initEClass(extReferenceDescriptionEClass, ExtReferenceDescription.class, "ExtReferenceDescription", !EPackageImpl.IS_ABSTRACT, !EPackageImpl.IS_INTERFACE, //$NON-NLS-1$
+                EPackageImpl.IS_GENERATED_INSTANCE_CLASS);
+        initEAttribute(getExtReferenceDescription_ReferenceNameExpression(), theDescriptionPackage.getInterpretedExpression(), "referenceNameExpression", null, 1, 1, ExtReferenceDescription.class, //$NON-NLS-1$
+                !EPackageImpl.IS_TRANSIENT, !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, !EPackageImpl.IS_UNSETTABLE, !EPackageImpl.IS_ID, EPackageImpl.IS_UNIQUE, !EPackageImpl.IS_DERIVED,
+                EPackageImpl.IS_ORDERED);
+        initEAttribute(getExtReferenceDescription_ReferenceOwnerExpression(), theDescriptionPackage.getInterpretedExpression(), "referenceOwnerExpression", null, 0, 1, ExtReferenceDescription.class, //$NON-NLS-1$
+                !EPackageImpl.IS_TRANSIENT, !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, !EPackageImpl.IS_UNSETTABLE, !EPackageImpl.IS_ID, EPackageImpl.IS_UNIQUE, !EPackageImpl.IS_DERIVED,
+                EPackageImpl.IS_ORDERED);
+        initEReference(getExtReferenceDescription_Style(), this.getExtReferenceWidgetStyle(), null, "style", null, 0, 1, ExtReferenceDescription.class, !EPackageImpl.IS_TRANSIENT, //$NON-NLS-1$
+                !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, EPackageImpl.IS_COMPOSITE, !EPackageImpl.IS_RESOLVE_PROXIES, !EPackageImpl.IS_UNSETTABLE, EPackageImpl.IS_UNIQUE,
+                !EPackageImpl.IS_DERIVED, EPackageImpl.IS_ORDERED);
+        initEReference(getExtReferenceDescription_ConditionalStyles(), this.getExtReferenceWidgetConditionalStyle(), null, "conditionalStyles", null, 0, -1, ExtReferenceDescription.class, //$NON-NLS-1$
+                !EPackageImpl.IS_TRANSIENT, !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, EPackageImpl.IS_COMPOSITE, !EPackageImpl.IS_RESOLVE_PROXIES, !EPackageImpl.IS_UNSETTABLE,
+                EPackageImpl.IS_UNIQUE, !EPackageImpl.IS_DERIVED, EPackageImpl.IS_ORDERED);
+
+        initEClass(extReferenceWidgetStyleEClass, ExtReferenceWidgetStyle.class, "ExtReferenceWidgetStyle", !EPackageImpl.IS_ABSTRACT, !EPackageImpl.IS_INTERFACE, //$NON-NLS-1$
+                EPackageImpl.IS_GENERATED_INSTANCE_CLASS);
+
+        initEClass(extReferenceWidgetConditionalStyleEClass, ExtReferenceWidgetConditionalStyle.class, "ExtReferenceWidgetConditionalStyle", !EPackageImpl.IS_ABSTRACT, !EPackageImpl.IS_INTERFACE, //$NON-NLS-1$
+                EPackageImpl.IS_GENERATED_INSTANCE_CLASS);
+        initEReference(getExtReferenceWidgetConditionalStyle_Style(), this.getExtReferenceWidgetStyle(), null, "style", null, 0, 1, ExtReferenceWidgetConditionalStyle.class, //$NON-NLS-1$
+                !EPackageImpl.IS_TRANSIENT, !EPackageImpl.IS_VOLATILE, EPackageImpl.IS_CHANGEABLE, EPackageImpl.IS_COMPOSITE, !EPackageImpl.IS_RESOLVE_PROXIES, !EPackageImpl.IS_UNSETTABLE,
+                EPackageImpl.IS_UNIQUE, !EPackageImpl.IS_DERIVED, EPackageImpl.IS_ORDERED);
 
         // Create resource
         createResource(PropertiesExtWidgetsReferencePackage.eNS_URI);
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceAdapterFactory.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceAdapterFactory.java
index bd7ad390cd..89d7aa444d 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceAdapterFactory.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceAdapterFactory.java
@@ -16,8 +16,12 @@ import org.eclipse.emf.common.notify.Notifier;
 import org.eclipse.emf.common.notify.impl.AdapterFactoryImpl;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.sirius.properties.ControlDescription;
+import org.eclipse.sirius.properties.WidgetConditionalStyle;
 import org.eclipse.sirius.properties.WidgetDescription;
+import org.eclipse.sirius.properties.WidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
 
 /**
@@ -81,6 +85,16 @@ public class PropertiesExtWidgetsReferenceAdapterFactory extends AdapterFactoryI
         }
 
         @Override
+        public Adapter caseExtReferenceWidgetStyle(ExtReferenceWidgetStyle object) {
+            return createExtReferenceWidgetStyleAdapter();
+        }
+
+        @Override
+        public Adapter caseExtReferenceWidgetConditionalStyle(ExtReferenceWidgetConditionalStyle object) {
+            return createExtReferenceWidgetConditionalStyleAdapter();
+        }
+
+        @Override
         public Adapter caseControlDescription(ControlDescription object) {
             return createControlDescriptionAdapter();
         }
@@ -91,6 +105,16 @@ public class PropertiesExtWidgetsReferenceAdapterFactory extends AdapterFactoryI
         }
 
         @Override
+        public Adapter caseWidgetStyle(WidgetStyle object) {
+            return createWidgetStyleAdapter();
+        }
+
+        @Override
+        public Adapter caseWidgetConditionalStyle(WidgetConditionalStyle object) {
+            return createWidgetConditionalStyleAdapter();
+        }
+
+        @Override
         public Adapter defaultCase(EObject object) {
             return createEObjectAdapter();
         }
@@ -128,6 +152,38 @@ public class PropertiesExtWidgetsReferenceAdapterFactory extends AdapterFactoryI
 
     /**
      * Creates a new adapter for an object of class '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle
+     * <em>Ext Reference Widget Style</em>}'. <!-- begin-user-doc --> This
+     * default implementation returns null so that we can easily ignore cases;
+     * it's useful to ignore a case when inheritance will catch all the cases
+     * anyway. <!-- end-user-doc -->
+     *
+     * @return the new adapter.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle
+     * @generated
+     */
+    public Adapter createExtReferenceWidgetStyleAdapter() {
+        return null;
+    }
+
+    /**
+     * Creates a new adapter for an object of class '
+     * {@link org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle
+     * <em>Ext Reference Widget Conditional Style</em>}'. <!-- begin-user-doc
+     * --> This default implementation returns null so that we can easily ignore
+     * cases; it's useful to ignore a case when inheritance will catch all the
+     * cases anyway. <!-- end-user-doc -->
+     *
+     * @return the new adapter.
+     * @see org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle
+     * @generated
+     */
+    public Adapter createExtReferenceWidgetConditionalStyleAdapter() {
+        return null;
+    }
+
+    /**
+     * Creates a new adapter for an object of class '
      * {@link org.eclipse.sirius.properties.ControlDescription
      * <em>Control Description</em>}'. <!-- begin-user-doc --> This default
      * implementation returns null so that we can easily ignore cases; it's
@@ -159,6 +215,37 @@ public class PropertiesExtWidgetsReferenceAdapterFactory extends AdapterFactoryI
     }
 
     /**
+     * Creates a new adapter for an object of class '
+     * {@link org.eclipse.sirius.properties.WidgetStyle <em>Widget Style</em>}'.
+     * <!-- begin-user-doc --> This default implementation returns null so that
+     * we can easily ignore cases; it's useful to ignore a case when inheritance
+     * will catch all the cases anyway. <!-- end-user-doc -->
+     *
+     * @return the new adapter.
+     * @see org.eclipse.sirius.properties.WidgetStyle
+     * @generated
+     */
+    public Adapter createWidgetStyleAdapter() {
+        return null;
+    }
+
+    /**
+     * Creates a new adapter for an object of class '
+     * {@link org.eclipse.sirius.properties.WidgetConditionalStyle
+     * <em>Widget Conditional Style</em>}'. <!-- begin-user-doc --> This default
+     * implementation returns null so that we can easily ignore cases; it's
+     * useful to ignore a case when inheritance will catch all the cases anyway.
+     * <!-- end-user-doc -->
+     *
+     * @return the new adapter.
+     * @see org.eclipse.sirius.properties.WidgetConditionalStyle
+     * @generated
+     */
+    public Adapter createWidgetConditionalStyleAdapter() {
+        return null;
+    }
+
+    /**
      * Creates a new adapter for the default case. <!-- begin-user-doc --> This
      * default implementation returns null. <!-- end-user-doc -->
      *
diff --git a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceSwitch.java b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceSwitch.java
index 3ce663cca1..25ac09d8f0 100644
--- a/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceSwitch.java
+++ b/plugins/org.eclipse.sirius.properties.ext.widgets.reference/src-gen/org/eclipse/sirius/properties/ext/widgets/reference/propertiesextwidgetsreference/util/PropertiesExtWidgetsReferenceSwitch.java
@@ -15,8 +15,12 @@ import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EPackage;
 import org.eclipse.emf.ecore.util.Switch;
 import org.eclipse.sirius.properties.ControlDescription;
+import org.eclipse.sirius.properties.WidgetConditionalStyle;
 import org.eclipse.sirius.properties.WidgetDescription;
+import org.eclipse.sirius.properties.WidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.PropertiesExtWidgetsReferencePackage;
 
 /**
@@ -89,6 +93,28 @@ public class PropertiesExtWidgetsReferenceSwitch<T> extends Switch<T> {
             }
             return result;
         }
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_STYLE: {
+            ExtReferenceWidgetStyle extReferenceWidgetStyle = (ExtReferenceWidgetStyle) theEObject;
+            T result = caseExtReferenceWidgetStyle(extReferenceWidgetStyle);
+            if (result == null) {
+                result = caseWidgetStyle(extReferenceWidgetStyle);
+            }
+            if (result == null) {
+                result = defaultCase(theEObject);
+            }
+            return result;
+        }
+        case PropertiesExtWidgetsReferencePackage.EXT_REFERENCE_WIDGET_CONDITIONAL_STYLE: {
+            ExtReferenceWidgetConditionalStyle extReferenceWidgetConditionalStyle = (ExtReferenceWidgetConditionalStyle) theEObject;
+            T result = caseExtReferenceWidgetConditionalStyle(extReferenceWidgetConditionalStyle);
+            if (result == null) {
+                result = caseWidgetConditionalStyle(extReferenceWidgetConditionalStyle);
+            }
+            if (result == null) {
+                result = defaultCase(theEObject);
+            }
+            return result;
+        }
         default:
             return defaultCase(theEObject);
         }
@@ -113,6 +139,40 @@ public class PropertiesExtWidgetsReferenceSwitch<T> extends Switch<T> {
 
     /**
      * Returns the result of interpreting the object as an instance of '
+     * <em>Ext Reference Widget Style</em>'. <!-- begin-user-doc --> This
+     * implementation returns null; returning a non-null result will terminate
+     * the switch. <!-- end-user-doc -->
+     *
+     * @param object
+     *            the target of the switch.
+     * @return the result of interpreting the object as an instance of '
+     *         <em>Ext Reference Widget Style</em>'.
+     * @see #doSwitch(org.eclipse.emf.ecore.EObject) doSwitch(EObject)
+     * @generated
+     */
+    public T caseExtReferenceWidgetStyle(ExtReferenceWidgetStyle object) {
+        return null;
+    }
+
+    /**
+     * Returns the result of interpreting the object as an instance of '
+     * <em>Ext Reference Widget Conditional Style</em>'. <!-- begin-user-doc -->
+     * This implementation returns null; returning a non-null result will
+     * terminate the switch. <!-- end-user-doc -->
+     *
+     * @param object
+     *            the target of the switch.
+     * @return the result of interpreting the object as an instance of '
+     *         <em>Ext Reference Widget Conditional Style</em>'.
+     * @see #doSwitch(org.eclipse.emf.ecore.EObject) doSwitch(EObject)
+     * @generated
+     */
+    public T caseExtReferenceWidgetConditionalStyle(ExtReferenceWidgetConditionalStyle object) {
+        return null;
+    }
+
+    /**
+     * Returns the result of interpreting the object as an instance of '
      * <em>Control Description</em>'. <!-- begin-user-doc --> This
      * implementation returns null; returning a non-null result will terminate
      * the switch. <!-- end-user-doc -->
@@ -147,6 +207,40 @@ public class PropertiesExtWidgetsReferenceSwitch<T> extends Switch<T> {
 
     /**
      * Returns the result of interpreting the object as an instance of '
+     * <em>Widget Style</em>'. <!-- begin-user-doc --> This implementation
+     * returns null; returning a non-null result will terminate the switch. <!--
+     * end-user-doc -->
+     *
+     * @param object
+     *            the target of the switch.
+     * @return the result of interpreting the object as an instance of '
+     *         <em>Widget Style</em>'.
+     * @see #doSwitch(org.eclipse.emf.ecore.EObject) doSwitch(EObject)
+     * @generated
+     */
+    public T caseWidgetStyle(WidgetStyle object) {
+        return null;
+    }
+
+    /**
+     * Returns the result of interpreting the object as an instance of '
+     * <em>Widget Conditional Style</em>'. <!-- begin-user-doc --> This
+     * implementation returns null; returning a non-null result will terminate
+     * the switch. <!-- end-user-doc -->
+     *
+     * @param object
+     *            the target of the switch.
+     * @return the result of interpreting the object as an instance of '
+     *         <em>Widget Conditional Style</em>'.
+     * @see #doSwitch(org.eclipse.emf.ecore.EObject) doSwitch(EObject)
+     * @generated
+     */
+    public T caseWidgetConditionalStyle(WidgetConditionalStyle object) {
+        return null;
+    }
+
+    /**
+     * Returns the result of interpreting the object as an instance of '
      * <em>EObject</em>'. <!-- begin-user-doc --> This implementation returns
      * null; returning a non-null result will terminate the switch, but this is
      * the last case anyway. <!-- end-user-doc -->
diff --git a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.properties b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.properties
index deb7b89fef..030a9c2077 100644
--- a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.properties
+++ b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.properties
@@ -14,6 +14,10 @@ providerName = Eclipse Modeling Project
 
 referenceDescriptionConverter.Label=Sirius Extension Reference Widget Converter
 referenceDescriptionConverter.Description=This extension is used to convert the definition of the Extension Reference Widget.
+referenceDescriptionStyleConverter.Label=Sirius Extension Reference Widget Style Converter
+referenceDescriptionStyleConverter.Description=This extension is used to convert the definition of the style of the Extension Reference Widget.
+referenceDescriptionConditionalStyleConverter.Label=Sirius Extension Reference Widget Conditional Style Converter
+referenceDescriptionConditionalStyleConverter.Description=This extension is used to convert the definition of the conditional style of the Extension Reference Widget.
 
 viewerFilterProvider.Label=Sirius Viewer Filter Provider
 viewerFilterProvider.Description=This extension is used to filter the content of the tree viewer used to select and create a value in the Extension Reference Widget.
diff --git a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.xml b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.xml
index fb9d9b92f3..5ff7e89a26 100644
--- a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.xml
+++ b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/plugin.xml
@@ -9,9 +9,18 @@
             id="org.eclipse.sirius.ui.properties.ext.widgets.reference.descriptionConverter"
             label="%referenceDescriptionConverter.Label">
       </descriptor>
-   </extension>
-   <extension
-         point="org.eclipse.sirius.ui.properties.descriptionConverter">
+      <descriptor
+            class="org.eclipse.sirius.ui.properties.ext.widgets.reference.internal.ExtReferenceDescriptionStyleConverter"
+            description="%referenceDescriptionStyleConverter.Description"
+            id="org.eclipse.sirius.ui.properties.ext.widgets.reference.descriptionStyleConverter"
+            label="%referenceDescriptionStyleConverter.Label">
+      </descriptor>
+      <descriptor
+            class="org.eclipse.sirius.ui.properties.ext.widgets.reference.internal.ExtReferenceDescriptionConditionalStyleConverter"
+            description="%referenceDescriptionConditionalStyleConverter.Description"
+            id="org.eclipse.sirius.ui.properties.ext.widgets.reference.descriptionConditionalStyleConverter"
+            label="%referenceDescriptionConditionalStyleConverter.Label">
+      </descriptor>
       <descriptor
             class="org.eclipse.sirius.ui.properties.ext.widgets.reference.internal.DefaultRulesReferenceDescriptionConverter"
             description="%defaultRulesReferenceDescriptionConverter.Description"
diff --git a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConditionalStyleConverter.java b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConditionalStyleConverter.java
new file mode 100644
index 0000000000..8ab74bf8eb
--- /dev/null
+++ b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConditionalStyleConverter.java
@@ -0,0 +1,37 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.ui.properties.ext.widgets.reference.internal;
+
+import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EefExtWidgetsReferenceFactory;
+import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EefExtWidgetsReferencePackage;
+import org.eclipse.emf.ecore.EFactory;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetConditionalStyle;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionConverter;
+
+/**
+ * The converter of the conditional style.
+ * 
+ * @author sbegaudeau
+ */
+public class ExtReferenceDescriptionConditionalStyleConverter extends DefaultDescriptionConverter<ExtReferenceWidgetConditionalStyle> {
+
+    /**
+     * The constructor.
+     */
+    public ExtReferenceDescriptionConditionalStyleConverter() {
+        super(ExtReferenceWidgetConditionalStyle.class, EefExtWidgetsReferencePackage.Literals.EEF_EXT_REFERENCE_CONDITIONAL_STYLE);
+    }
+
+    @Override
+    protected EFactory getEFactory() {
+        return EefExtWidgetsReferenceFactory.eINSTANCE;
+    }
+}
diff --git a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConverter.java
index 642fc3bd06..9bd48f0262 100644
--- a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionConverter.java
@@ -10,14 +10,11 @@
  */
 package org.eclipse.sirius.ui.properties.ext.widgets.reference.internal;
 
-import java.util.Map;
-
-import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EEFExtReferenceDescription;
 import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EefExtWidgetsReferenceFactory;
-import org.eclipse.emf.ecore.EObject;
+import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EefExtWidgetsReferencePackage;
+import org.eclipse.emf.ecore.EFactory;
 import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceDescription;
-import org.eclipse.sirius.ui.properties.api.DescriptionCache;
-import org.eclipse.sirius.ui.properties.api.IDescriptionConverter;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionConverter;
 
 /**
  * This class is used to convert the Sirius Extension reference description into
@@ -25,30 +22,17 @@ import org.eclipse.sirius.ui.properties.api.IDescriptionConverter;
  * 
  * @author sbegaudeau
  */
-public class ExtReferenceDescriptionConverter implements IDescriptionConverter {
+public class ExtReferenceDescriptionConverter extends DefaultDescriptionConverter<ExtReferenceDescription> {
 
-    @Override
-    public boolean canHandle(EObject description) {
-        return description instanceof ExtReferenceDescription;
+    /**
+     * The constructor.
+     */
+    public ExtReferenceDescriptionConverter() {
+        super(ExtReferenceDescription.class, EefExtWidgetsReferencePackage.Literals.EEF_EXT_REFERENCE_DESCRIPTION);
     }
 
     @Override
-    public EObject convert(EObject description, Map<String, Object> parameters, DescriptionCache cache) {
-        if (description instanceof ExtReferenceDescription) {
-            ExtReferenceDescription extReferenceDescription = (ExtReferenceDescription) description;
-
-            EEFExtReferenceDescription eefExtReferenceDescription = EefExtWidgetsReferenceFactory.eINSTANCE.createEEFExtReferenceDescription();
-            eefExtReferenceDescription.setIdentifier(extReferenceDescription.getIdentifier());
-            eefExtReferenceDescription.setHelpExpression(extReferenceDescription.getHelpExpression());
-            eefExtReferenceDescription.setIsEnabledExpression(extReferenceDescription.getIsEnabledExpression());
-            eefExtReferenceDescription.setLabelExpression(extReferenceDescription.getLabelExpression());
-            eefExtReferenceDescription.setReferenceNameExpression(extReferenceDescription.getReferenceNameExpression());
-            eefExtReferenceDescription.setReferenceOwnerExpression(extReferenceDescription.getReferenceOwnerExpression());
-
-            cache.put(extReferenceDescription, eefExtReferenceDescription);
-
-            return eefExtReferenceDescription;
-        }
-        return null;
+    protected EFactory getEFactory() {
+        return EefExtWidgetsReferenceFactory.eINSTANCE;
     }
 }
diff --git a/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionStyleConverter.java b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionStyleConverter.java
new file mode 100644
index 0000000000..406a0dca67
--- /dev/null
+++ b/plugins/org.eclipse.sirius.ui.properties.ext.widgets.reference/src/org/eclipse/sirius/ui/properties/ext/widgets/reference/internal/ExtReferenceDescriptionStyleConverter.java
@@ -0,0 +1,38 @@
+/**
+ * Copyright (c) 2016 Obeo.
+ * 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.ui.properties.ext.widgets.reference.internal;
+
+import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EefExtWidgetsReferenceFactory;
+import org.eclipse.eef.ext.widgets.reference.eefextwidgetsreference.EefExtWidgetsReferencePackage;
+import org.eclipse.emf.ecore.EFactory;
+import org.eclipse.sirius.properties.ext.widgets.reference.propertiesextwidgetsreference.ExtReferenceWidgetStyle;
+import org.eclipse.sirius.ui.properties.api.DefaultStyleDescriptionConverter;
+
+/**
+ * Converter for the style of the reference widget.
+ * 
+ * @author sbegaudeau
+ */
+public class ExtReferenceDescriptionStyleConverter extends DefaultStyleDescriptionConverter<ExtReferenceWidgetStyle> {
+
+    /**
+     * The constructor.
+     */
+    public ExtReferenceDescriptionStyleConverter() {
+        super(ExtReferenceWidgetStyle.class, EefExtWidgetsReferencePackage.Literals.EEF_EXT_REFERENCE_WIDGET_STYLE);
+    }
+
+    @Override
+    protected EFactory getEFactory() {
+        return EefExtWidgetsReferenceFactory.eINSTANCE;
+    }
+
+}
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/AbstractDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/AbstractDescriptionConverter.java
index 3289f28b04..2aa4ffa221 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/AbstractDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/AbstractDescriptionConverter.java
@@ -8,7 +8,7 @@
  * Contributors:
  *    Obeo - initial API and implementation
  *******************************************************************************/
-package org.eclipse.sirius.ui.properties.internal.tabprovider;
+package org.eclipse.sirius.ui.properties.api;
 
 import java.text.MessageFormat;
 import java.util.ArrayList;
@@ -19,8 +19,6 @@ import java.util.Map;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.sirius.business.api.color.AbstractColorUpdater;
-import org.eclipse.sirius.ui.properties.api.DescriptionCache;
-import org.eclipse.sirius.ui.properties.api.IDescriptionConverter;
 import org.eclipse.sirius.ui.properties.internal.SiriusInputDescriptor;
 import org.eclipse.sirius.ui.properties.internal.SiriusUIPropertiesPlugin;
 import org.eclipse.sirius.viewpoint.RGBValues;
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/DefaultDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/DefaultDescriptionConverter.java
index 2950642081..b38860adc1 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/DefaultDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/DefaultDescriptionConverter.java
@@ -8,7 +8,7 @@
  * Contributors:
  *    Obeo - initial API and implementation
  *******************************************************************************/
-package org.eclipse.sirius.ui.properties.internal.tabprovider;
+package org.eclipse.sirius.ui.properties.api;
 
 import java.text.MessageFormat;
 import java.util.ArrayList;
@@ -19,11 +19,11 @@ import java.util.Map;
 import org.eclipse.eef.EefFactory;
 import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.emf.ecore.EClass;
+import org.eclipse.emf.ecore.EFactory;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.EcorePackage;
-import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.ui.properties.internal.Messages;
 
 /**
@@ -70,7 +70,7 @@ public class DefaultDescriptionConverter<SIRIUS extends EObject> extends Abstrac
         if (this.siriusClass.isAssignableFrom(description.getClass())) {
             SIRIUS siriusEObject = this.siriusClass.cast(description);
 
-            EObject eefEObject = EefFactory.eINSTANCE.create(this.eefEClass);
+            EObject eefEObject = this.getEFactory().create(this.eefEClass);
             for (EAttribute eAttribute : siriusEObject.eClass().getEAllAttributes()) {
                 this.convertEAttribute(siriusEObject, eefEObject, eAttribute, parameters);
             }
@@ -88,6 +88,15 @@ public class DefaultDescriptionConverter<SIRIUS extends EObject> extends Abstrac
     }
 
     /**
+     * Returns the factory to use to create the new EEF Object.
+     * 
+     * @return The {@link EFactory}
+     */
+    protected EFactory getEFactory() {
+        return EefFactory.eINSTANCE;
+    }
+
+    /**
      * Converts the value of the given Sirius EAttribute from the Sirius EObject
      * to the given EEF EObject.
      * 
@@ -167,4 +176,5 @@ public class DefaultDescriptionConverter<SIRIUS extends EObject> extends Abstrac
         }
         return eObjects;
     }
+
 }
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/DefaultDescriptionWithInitialOperationConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/DefaultDescriptionWithInitialOperationConverter.java
index 0fc54ef11a..c1d3dc0b2f 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/DefaultDescriptionWithInitialOperationConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/DefaultDescriptionWithInitialOperationConverter.java
@@ -8,7 +8,7 @@
  * Contributors:
  *    Obeo - initial API and implementation
  *******************************************************************************/
-package org.eclipse.sirius.ui.properties.internal.tabprovider;
+package org.eclipse.sirius.ui.properties.api;
 
 import java.util.Map;
 
@@ -16,7 +16,6 @@ import org.eclipse.emf.ecore.EAttribute;
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
-import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.viewpoint.description.tool.InitialOperation;
 import org.eclipse.sirius.viewpoint.description.tool.ToolPackage;
 
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/DefaultStyleDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/DefaultStyleDescriptionConverter.java
index fe4df3ec12..93236924d7 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/DefaultStyleDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/api/DefaultStyleDescriptionConverter.java
@@ -8,7 +8,7 @@
  * Contributors:
  *    Obeo - initial API and implementation
  *******************************************************************************/
-package org.eclipse.sirius.ui.properties.internal.tabprovider;
+package org.eclipse.sirius.ui.properties.api;
 
 import java.util.Map;
 
@@ -17,7 +17,6 @@ import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EStructuralFeature;
-import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.viewpoint.description.ColorDescription;
 
 /**
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/SiriusUIPropertiesPlugin.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/SiriusUIPropertiesPlugin.java
index 5468723b34..c99e46babb 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/SiriusUIPropertiesPlugin.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/SiriusUIPropertiesPlugin.java
@@ -25,10 +25,10 @@ import org.eclipse.eef.ide.api.extensions.impl.ItemRegistry;
 import org.eclipse.emf.common.EMFPlugin;
 import org.eclipse.emf.common.util.ResourceLocator;
 import org.eclipse.emf.ecore.EObject;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionConverter;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionWithInitialOperationConverter;
 import org.eclipse.sirius.ui.properties.api.IDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.IDescriptionLinkResolver;
-import org.eclipse.sirius.ui.properties.internal.tabprovider.DefaultDescriptionConverter;
-import org.eclipse.sirius.ui.properties.internal.tabprovider.DefaultDescriptionWithInitialOperationConverter;
 import org.eclipse.sirius.ui.properties.internal.tabprovider.PropertiesDescriptionConverterSwitch;
 import org.eclipse.sirius.ui.properties.internal.tabprovider.PropertyValidationRuleLinkResolver;
 import org.eclipse.sirius.ui.properties.internal.tabprovider.SemanticValidationRuleDescriptionConverter;
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/AbstractValidationRuleDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/AbstractValidationRuleDescriptionConverter.java
index 7fc4f1f9ec..d7e87c5e5e 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/AbstractValidationRuleDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/AbstractValidationRuleDescriptionConverter.java
@@ -16,6 +16,7 @@ import org.eclipse.eef.EEFRuleAuditDescription;
 import org.eclipse.eef.EEFValidationFixDescription;
 import org.eclipse.eef.EEFValidationRuleDescription;
 import org.eclipse.eef.EEF_VALIDATION_SEVERITY_DESCRIPTION;
+import org.eclipse.sirius.ui.properties.api.AbstractDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.viewpoint.description.validation.ERROR_LEVEL;
 import org.eclipse.sirius.viewpoint.description.validation.ValidationRule;
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/CustomWidgetDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/CustomWidgetDescriptionConverter.java
index 8e6b210982..2a30394a15 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/CustomWidgetDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/CustomWidgetDescriptionConverter.java
@@ -21,6 +21,7 @@ import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EReference;
 import org.eclipse.sirius.properties.PropertiesPackage;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 
 /**
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupDescriptionConverter.java
index 822bb42f2a..9196bc920e 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupDescriptionConverter.java
@@ -25,6 +25,7 @@ import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.sirius.properties.GroupDescription;
 import org.eclipse.sirius.properties.GroupValidationSetDescription;
+import org.eclipse.sirius.ui.properties.api.AbstractDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.ui.properties.internal.Messages;
 
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupStyleDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupStyleDescriptionConverter.java
index de1585c998..19618fdfb5 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupStyleDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/GroupStyleDescriptionConverter.java
@@ -19,6 +19,7 @@ import org.eclipse.eef.EEF_TOGGLE_STYLE;
 import org.eclipse.eef.EefFactory;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.sirius.properties.GroupStyle;
+import org.eclipse.sirius.ui.properties.api.AbstractDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.ui.properties.internal.Messages;
 import org.eclipse.sirius.viewpoint.description.ColorDescription;
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PageDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PageDescriptionConverter.java
index ec0c48b31c..c3723babfa 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PageDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PageDescriptionConverter.java
@@ -20,6 +20,7 @@ import org.eclipse.eef.EefFactory;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.util.EcoreUtil;
 import org.eclipse.sirius.properties.PageDescription;
+import org.eclipse.sirius.ui.properties.api.AbstractDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.ui.properties.internal.Messages;
 import org.eclipse.sirius.viewpoint.description.validation.SemanticValidationRule;
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PropertiesDescriptionConverterSwitch.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PropertiesDescriptionConverterSwitch.java
index 3a8bf25de9..79982e2223 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PropertiesDescriptionConverterSwitch.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/PropertiesDescriptionConverterSwitch.java
@@ -53,6 +53,9 @@ import org.eclipse.sirius.properties.TextWidgetConditionalStyle;
 import org.eclipse.sirius.properties.TextWidgetStyle;
 import org.eclipse.sirius.properties.WidgetAction;
 import org.eclipse.sirius.properties.util.PropertiesSwitch;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionConverter;
+import org.eclipse.sirius.ui.properties.api.DefaultDescriptionWithInitialOperationConverter;
+import org.eclipse.sirius.ui.properties.api.DefaultStyleDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.IDescriptionConverter;
 
 /**
diff --git a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/TextDescriptionConverter.java b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/TextDescriptionConverter.java
index c03517c670..5bb914018b 100644
--- a/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/TextDescriptionConverter.java
+++ b/plugins/org.eclipse.sirius.ui.properties/src/org/eclipse/sirius/ui/properties/internal/tabprovider/TextDescriptionConverter.java
@@ -20,6 +20,7 @@ import org.eclipse.eef.EefFactory;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.sirius.properties.TextAreaDescription;
 import org.eclipse.sirius.properties.TextDescription;
+import org.eclipse.sirius.ui.properties.api.AbstractDescriptionConverter;
 import org.eclipse.sirius.ui.properties.api.DescriptionCache;
 import org.eclipse.sirius.ui.properties.internal.Messages;
 import org.eclipse.sirius.viewpoint.description.tool.InitialOperation;