java.lang.AssertionError
   at org.openide.text.CloneableEditor$DoInitialize.initNonVisual(CloneableEditor.java:592)
   at org.openide.text.CloneableEditor$DoInitialize.run(CloneableEditor.java:332)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1424)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1968)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError
   at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:1465)
   at org.openide.text.CloneableEditor$DoInitialize.<init>(CloneableEditor.java:297)
   at org.openide.text.CloneableEditor.initialize(CloneableEditor.java:232)
   at org.openide.text.CloneableEditor.componentShowing(CloneableEditor.java:208)
   at org.openide.windows.WindowManager.componentShowing(WindowManager.java:339)
   at org.netbeans.core.windows.WindowManagerImpl.componentShowing(WindowManagerImpl.java:1025)
   at org.netbeans.core.windows.view.DefaultView.changeGUI(DefaultView.java:164)
   at org.netbeans.core.windows.ViewRequestor.dispatchRequest(ViewRequestor.java:272)
   at org.netbeans.core.windows.ViewRequestor.processRequest(ViewRequestor.java:248)
   at org.netbeans.core.windows.ViewRequestor.postRequest(ViewRequestor.java:186)
   at org.netbeans.core.windows.ViewRequestor.scheduleRequest(ViewRequestor.java:126)
   at org.netbeans.core.windows.Central.removeModeTopComponent(Central.java:993)
   at org.netbeans.core.windows.ModeImpl.removeTopComponent(ModeImpl.java:417)
   at org.netbeans.core.windows.ModeImpl.close(ModeImpl.java:246)
   at org.netbeans.core.windows.WindowManagerImpl.topComponentClose(WindowManagerImpl.java:1136)
   at org.openide.windows.TopComponent.close(TopComponent.java:567)
   at org.openide.windows.TopComponent.close(TopComponent.java:554)
   at org.openide.windows.CloneableOpenSupport$2.run(CloneableOpenSupport.java:158)
   at org.openide.windows.CloneableOpenSupport$2.run(CloneableOpenSupport.java:144)
   at org.openide.util.Mutex.doEventAccess(Mutex.java:1361)
   at org.openide.util.Mutex.writeAccess(Mutex.java:380)
   at org.openide.windows.CloneableOpenSupport.close(CloneableOpenSupport.java:143)
   at org.openide.text.CloneableEditorSupport.close(CloneableEditorSupport.java:2195)
   at org.netbeans.modules.java.JavaDataObject$JavaEditorSupport.close(JavaDataObject.java:207)
   at org.openide.windows.CloneableOpenSupport$Listener.run(CloneableOpenSupport.java:348)
   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:148)
   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)