@Override\r
protected boolean shouldCreateToolTip(Event event) {\r
TreeItem treeItem = parent.getItem(new Point(event.x, event.y));\r
+ if (treeItem == null)\r
+ return false;\r
GENodeQueryManager manager = new GENodeQueryManager(explorerContext, null, null, TreeItemReference.create(treeItem.getParentItem()));\r
nodeContext = (NodeContext) treeItem.getData();\r
labeler = manager.query(nodeContext, BuiltinKeys.SELECTED_LABELER);\r