#2822 Fix for Richtext description

If the tracked element is owned by a closed session, do no save it

Change-Id: Icc0819da76221c5c2be21a23ae834ff54981270e
Signed-off-by: Erwann Traisnel <erwann.traisnel@obeo.fr>

core/plugins/org.polarsys.capella.core.ui.properties.richtext/src/org/polarsys/capella/core/ui/properties/richtext/fields/ElementDescriptionGroup.java

@@ -22,6 +22,8 @@
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.jface.layout.GridLayoutFactory;
+import org.eclipse.sirius.business.api.session.Session;
+import org.eclipse.sirius.business.api.session.SessionManager;
 import org.eclipse.sirius.common.tools.api.query.IllegalStateExceptionQuery;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTException;
@@ -211,7 +213,7 @@ protected void checkSubclass() {
   public void aboutToBeShown() {
     if (updateDescriptionEditability(semanticElement, semanticFeature)) {
       try {
-        if (semanticElement != null && semanticFeature != null) {
+        if (semanticElement != null && semanticFeature != null) {          
           ((SavingStrategy) descriptionTextField.getSaveStrategy()).ensureLastSave();
           descriptionTextField.bind(semanticElement, semanticFeature);
           descriptionTextField.setSaveStrategy(new SavingStrategy(semanticElement, semanticFeature));
@@ -233,6 +235,12 @@ public void aboutToBeShown() {
    * Remove the editor before the Property tab is disposed
    */
   public void aboutToBeHidden() {
+    Session session = SessionManager.INSTANCE.getSession(semanticElement);
+    if(session == null) {
+      //If the semanticElement doesn't belong to a session, clear it 
+      semanticElement = null;
+      semanticFeature = null;
+    }
     hideEditor();
   }