java.lang.NullPointerException
        at org.netbeans.modules.form.FormDesigner.componentIds(FormDesigner.java:2133)
        at org.netbeans.modules.form.FormDesigner.updateResizabilityActions(FormDesigner.java:1059)
        at org.netbeans.modules.form.FormDesigner.selectionChanged(FormDesigner.java:1032)
        at org.netbeans.modules.form.FormDesigner.clearSelectionImpl(FormDesigner.java:1027)
        at org.netbeans.modules.form.ComponentInspector$NodeSelectionListener.propertyChange(ComponentInspector.java:515)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
        at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
        at org.openide.explorer.ExplorerManager$2.run(ExplorerManager.java:859)
        at org.openide.util.Mutex.doEvent(Mutex.java:1335)
        at org.openide.util.Mutex.readAccess(Mutex.java:345)
        at org.openide.explorer.ExplorerManager.fireInAWT(ExplorerManager.java:856)
        at org.openide.explorer.ExplorerManager$1AtomicSetSelectedNodes.fire(ExplorerManager.java:278)
        at org.openide.explorer.ExplorerManager.setSelectedNodes(ExplorerManager.java:289)
        at org.openide.explorer.ExplorerManager.setSelectedNodes0(ExplorerManager.java:439)
        at org.openide.explorer.ExplorerManager$1SetExploredContext.run(ExplorerManager.java:338)
        at org.openide.util.Mutex.readAccess(Mutex.java:362)
        at org.openide.util.Mutex$1R.run(Mutex.java:1301)
        at org.openide.util.Mutex.doWrapperAccess(Mutex.java:1318)
        at org.openide.util.Mutex.readAccess(Mutex.java:351)
        at org.openide.explorer.ExplorerManager.setExploredContext(ExplorerManager.java:355)
        at org.openide.explorer.ExplorerManager$1SetRootContext.run(ExplorerManager.java:489)
        at org.openide.util.Mutex.readAccess(Mutex.java:362)
        at org.openide.util.Mutex$1R.run(Mutex.java:1301)
        at org.openide.nodes.Children$ProjectManagerDeadlockDetector.execute(Children.java:1796)
        at org.openide.util.Mutex.doWrapperAccess(Mutex.java:1320)
        at org.openide.util.Mutex.readAccess(Mutex.java:351)
        at org.openide.explorer.ExplorerManager.setRootContext(ExplorerManager.java:494)
        at org.netbeans.modules.form.ComponentInspector.focusFormImpl(ComponentInspector.java:307)
        at org.netbeans.modules.form.ComponentInspector.focusFormInAwtThread(ComponentInspector.java:270)
        at org.netbeans.modules.form.ComponentInspector.focusForm(ComponentInspector.java:255)
        at org.netbeans.modules.form.FormEditor.closeForm(FormEditor.java:757)
        at org.netbeans.modules.form.FormEditorSupport$3.run(FormEditorSupport.java:444)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)