java.lang.NullPointerException at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1009) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1025) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1031) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.adjustRowBy(FixedHeightLayoutCache.java:1031) at javax.swing.tree.FixedHeightLayoutCache$FHTreeStateNode.removeChildAtModelIndex(FixedHeightLayoutCache.java:1265) at javax.swing.tree.FixedHeightLayoutCache.treeNodesRemoved(FixedHeightLayoutCache.java:447) at javax.swing.plaf.basic.BasicTreeUI$Handler.treeNodesRemoved(BasicTreeUI.java:3849) at javax.swing.tree.DefaultTreeModel.fireTreeNodesRemoved(DefaultTreeModel.java:546) at javax.swing.tree.DefaultTreeModel.nodesWereRemoved(DefaultTreeModel.java:326) at org.openide.explorer.view.NodeTreeModel$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:226) at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:670) at java.awt.EventQueue.access$400(EventQueue.java:96) at java.awt.EventQueue$2.run(EventQueue.java:631) at java.awt.EventQueue$2.run(EventQueue.java:629) at java.security.AccessController.doPrivileged(AccessController.java:0) at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:105) at java.awt.EventQueue.dispatchEvent(EventQueue.java:640) at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:275) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:200) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:185) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:177) at java.awt.EventDispatchThread.run(EventDispatchThread.java:138)