java.lang.NullPointerException
   at javax.swing.plaf.basic.BasicTreeUI.completeEditing(BasicTreeUI.java:2073)
   at javax.swing.plaf.basic.BasicTreeUI$Handler.editingStopped(BasicTreeUI.java:3690)
   at javax.swing.AbstractCellEditor.fireEditingStopped(AbstractCellEditor.java:141)
   at javax.swing.DefaultCellEditor$EditorDelegate.stopCellEditing(DefaultCellEditor.java:368)
   at javax.swing.DefaultCellEditor.stopCellEditing(DefaultCellEditor.java:233)
   at javax.swing.tree.DefaultTreeCellEditor.stopCellEditing(DefaultTreeCellEditor.java:305)
   at javax.swing.plaf.basic.BasicTreeUI.completeEditing(BasicTreeUI.java:2034)
   at javax.swing.plaf.basic.BasicTreeUI$Handler.valueChanged(BasicTreeUI.java:3706)
   at javax.swing.tree.DefaultTreeSelectionModel.fireValueChanged(DefaultTreeSelectionModel.java:634)
   at javax.swing.tree.DefaultTreeSelectionModel.notifyPathChange(DefaultTreeSelectionModel.java:1092)
   at javax.swing.tree.DefaultTreeSelectionModel.removeSelectionPaths(DefaultTreeSelectionModel.java:501)
   at javax.swing.JTree.removeDescendantSelectedPaths(JTree.java:3710)
   at javax.swing.JTree.removeDescendantSelectedPaths(JTree.java:3760)
   at javax.swing.JTree$TreeModelHandler.treeNodesRemoved(JTree.java:3844)
   at org.openide.explorer.view.TreeView$ExplorerTree$ModelHandler.treeNodesRemoved(TreeView.java:2273)
   at javax.swing.tree.DefaultTreeModel.fireTreeNodesRemoved(DefaultTreeModel.java:548)
   at javax.swing.tree.DefaultTreeModel.nodesWereRemoved(DefaultTreeModel.java:328)
   at org.openide.explorer.view.NodeTreeModel$Listener.removed(NodeTreeModel.java:259)
   at org.openide.explorer.view.VisualizerChildren.removed(VisualizerChildren.java:290)
   at org.openide.explorer.view.VisualizerEvent$Removed.run(VisualizerEvent.java:135)
   at org.openide.util.Mutex.readAccess(Mutex.java:367)
   at org.openide.util.Mutex$1R.run(Mutex.java:1309)
   at org.openide.nodes.Children$ProjectManagerDeadlockDetector.execute(Children.java:1921)
   at org.openide.util.Mutex.doWrapperAccess(Mutex.java:1328)
   at org.openide.util.Mutex.readAccess(Mutex.java:356)
   at org.openide.explorer.view.VisualizerNode$QP.processQueue(VisualizerNode.java:685)
   at org.openide.explorer.view.VisualizerNode$QP.access$000(VisualizerNode.java:624)
   at org.openide.explorer.view.VisualizerNode$QP$ProcessQueue.run(VisualizerNode.java:706)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:727)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:688)
   at java.awt.EventQueue$3.run(EventQueue.java:686)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:697)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)