(should not happen but) prevent segfault if itemDelegate is null

src/domain/UBGraphicsScene.cpp

@@ -1335,9 +1335,12 @@ void UBGraphicsScene::updateSelectionFrame()
         mSelectionFrame->setEnclosedItems(QList<QGraphicsItem*>());
 
         UBGraphicsItemDelegate *itemDelegate = UBGraphicsItem::Delegate(selItems.first());
+        if (itemDelegate)
+        {
             itemDelegate->createControls();
             selItems.first()->setVisible(true);
             itemDelegate->showControls();
+        }
 
     } break;
     default: {