java.lang.AssertionError
   at org.openide.text.CloneableEditor$DoInitialize.initNonVisual(CloneableEditor.java:568)
   at org.openide.text.CloneableEditor$DoInitialize.run(CloneableEditor.java:324)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1417)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1955)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError
   at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:1455)
   at org.openide.text.CloneableEditor$DoInitialize.<init>(CloneableEditor.java:291)
   at org.openide.text.CloneableEditor.initialize(CloneableEditor.java:226)
   at org.openide.text.CloneableEditor.componentShowing(CloneableEditor.java:202)
   at org.openide.windows.WindowManager.componentShowing(WindowManager.java:332)
   at org.netbeans.core.windows.WindowManagerImpl.componentShowing(WindowManagerImpl.java:1022)
   at org.netbeans.core.windows.view.DefaultView.changeGUI(DefaultView.java:161)
   at org.netbeans.core.windows.ViewRequestor.dispatchRequest(ViewRequestor.java:269)
   at org.netbeans.core.windows.ViewRequestor.processRequest(ViewRequestor.java:245)
   at org.netbeans.core.windows.ViewRequestor.postRequest(ViewRequestor.java:183)
   at org.netbeans.core.windows.ViewRequestor.scheduleRequest(ViewRequestor.java:123)
   at org.netbeans.core.windows.Central.removeModeTopComponent(Central.java:990)
   at org.netbeans.core.windows.ModeImpl.removeTopComponent(ModeImpl.java:414)
   at org.netbeans.core.windows.ModeImpl.close(ModeImpl.java:243)
   at org.netbeans.core.windows.WindowManagerImpl.topComponentClose(WindowManagerImpl.java:1133)
   at org.openide.windows.TopComponent.close(TopComponent.java:552)
   at org.openide.windows.TopComponent.close(TopComponent.java:539)
   at org.openide.windows.CloneableOpenSupport$2.run(CloneableOpenSupport.java:155)
   at org.openide.windows.CloneableOpenSupport$2.run(CloneableOpenSupport.java:141)
   at org.openide.util.Mutex.doEventAccess(Mutex.java:1355)
   at org.openide.util.Mutex.writeAccess(Mutex.java:377)
   at org.openide.windows.CloneableOpenSupport.close(CloneableOpenSupport.java:140)
   at org.openide.text.CloneableEditorSupport.close(CloneableEditorSupport.java:2168)
   at org.netbeans.modules.csl.core.GsfDataObject$GenericEditorSupport.close(GsfDataObject.java:239)
   at org.openide.windows.CloneableOpenSupport$Listener.run(CloneableOpenSupport.java:345)
   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:133)
   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)