[477208] Avoid NPE when a part without semantic element is selected

This can occurs at least with Note, Text and NoteAttachment edit parts.

This has been discovered during reproduction attempt with a Note on the
diagram.

Bug: 477208
Change-Id: I4e175fdb4996ad00c484c64650f3075f7230bffe
Signed-off-by: Maxime Porhel <maxime.porhel@obeo.fr>

1 files changed, 11 insertions, 6 deletions

diff --git a/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/util/EditPartQuery.java b/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/util/EditPartQuery.java
index 24c6e4a5e3..f4590ac30a 100644
--- a/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/util/EditPartQuery.java
+++ b/plugins/org.eclipse.sirius.diagram.ui/src-diag/org/eclipse/sirius/diagram/ui/tools/internal/util/EditPartQuery.java
@@ -234,14 +234,19 @@ public class EditPartQuery {
      */
     public boolean isFreeFormContainerChildrenPresentation() {
         boolean isFreeForm = true;
-        EObject eContainer = part.resolveSemanticElement().eContainer();
-        if (eContainer instanceof DNodeList) {
+        EObject semElt = part.resolveSemanticElement();
+        if (semElt == null) {
             isFreeForm = false;
-        } else if (eContainer instanceof DNodeContainer) {
-            DNodeContainer container = (DNodeContainer) eContainer;
-            ContainerLayout childrenPresentation = container.getChildrenPresentation();
-            if (!childrenPresentation.equals(ContainerLayout.FREE_FORM)) {
+        } else {
+            EObject eContainer = semElt.eContainer();
+            if (eContainer instanceof DNodeList) {
                 isFreeForm = false;
+            } else if (eContainer instanceof DNodeContainer) {
+                DNodeContainer container = (DNodeContainer) eContainer;
+                ContainerLayout childrenPresentation = container.getChildrenPresentation();
+                if (!childrenPresentation.equals(ContainerLayout.FREE_FORM)) {
+                    isFreeForm = false;
+                }
             }
         }
         return isFreeForm;