QmlDesigner: Multiselection should be not empty

Change-Id: I0b1d0a0ed619d51932ac9a6f5415fb54efc723cc
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qmldesigner/components/componentcore/designeractionmanager.cpp

@@ -362,7 +362,7 @@ void DesignerActionManager::createDefaultDesignerActions()
 
     addDesignerAction(new SelectionModelNodeAction(selectionCategoryDisplayName, selectionCategory, prioritySelectionCategory));
 
-    addDesignerAction(new MenuDesignerAction(stackCategoryDisplayName, stackCategory, priorityStackCategory, &always));
+    addDesignerAction(new MenuDesignerAction(stackCategoryDisplayName, stackCategory, priorityStackCategory, &selectionNotEmpty));
         addDesignerAction(new ModelNodeAction
                    (toFrontDisplayName, stackCategory, 200, &toFront, &singleSelection));
         addDesignerAction(new ModelNodeAction