java.lang.AssertionError
   at org.openide.text.CloneableEditor$DoInitialize.initNonVisual(CloneableEditor.java:628)
   at org.openide.text.CloneableEditor$DoInitialize.run(CloneableEditor.java:367)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1452)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2032)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.AssertionError
   at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:1493)
   at org.openide.text.CloneableEditor$DoInitialize.<init>(CloneableEditor.java:332)
   at org.openide.text.CloneableEditor.initialize(CloneableEditor.java:248)
   at org.openide.text.CloneableEditor.componentShowing(CloneableEditor.java:223)
   at org.netbeans.core.spi.multiview.text.MultiViewCloneableEditor.componentShowing(MultiViewCloneableEditor.java:143)
   at org.netbeans.core.spi.multiview.text.MultiViewEditorElement.componentShowing(MultiViewEditorElement.java:134)
   at org.netbeans.core.multiview.MultiViewPeer.peerComponentShowing(MultiViewPeer.java:277)
   at org.netbeans.core.multiview.MultiViewCloneableTopComponent.componentShowing(MultiViewCloneableTopComponent.java:129)
   at org.openide.windows.WindowManager.componentShowing(WindowManager.java:339)
   at org.netbeans.core.windows.WindowManagerImpl.componentShowing(WindowManagerImpl.java:1163)
   at org.netbeans.core.windows.view.DefaultView.changeGUI(DefaultView.java:168)
   at org.netbeans.core.windows.ViewRequestor.dispatchRequest(ViewRequestor.java:273)
   at org.netbeans.core.windows.ViewRequestor.processRequest(ViewRequestor.java:249)
   at org.netbeans.core.windows.ViewRequestor.postRequest(ViewRequestor.java:187)
   at org.netbeans.core.windows.ViewRequestor.scheduleRequest(ViewRequestor.java:127)
   at org.netbeans.core.windows.Central.activateModeTopComponent(Central.java:1773)
   at org.netbeans.core.windows.WindowManagerImpl.topComponentRequestActive(WindowManagerImpl.java:1297)
   at org.openide.windows.TopComponent.requestActive(TopComponent.java:861)
   at org.openide.windows.CloneableOpenSupport$1.run(CloneableOpenSupport.java:102)
   at org.openide.util.Mutex.doEvent(Mutex.java:1341)
   at org.openide.util.Mutex.writeAccess(Mutex.java:455)
   at org.openide.windows.CloneableOpenSupport.open(CloneableOpenSupport.java:98)
   at org.openide.text.CloneableEditorSupport.open(CloneableEditorSupport.java:503)
   at org.openide.loaders.DefaultDataObject.open(DefaultDataObject.java:182)
   at org.openide.awt.ActionDefaultPerfomer.actionPerformed(ActionDefaultPerfomer.java:70)
   at org.openide.awt.ContextAction$Performer.actionPerformed(ContextAction.java:226)
   at org.openide.awt.ContextManager.actionPerformed(ContextManager.java:250)
   at org.openide.awt.ContextAction.actionPerformed(ContextAction.java:109)
   at org.openide.util.actions.ActionInvoker$1.run(ActionInvoker.java:93)
   at org.openide.util.actions.ActionInvoker.doPerformAction(ActionInvoker.java:116)
   at org.openide.util.actions.ActionInvoker.invokeAction(ActionInvoker.java:99)
   at org.openide.awt.GeneralAction$BaseDelAction.actionPerformed(GeneralAction.java:234)
   at org.openide.explorer.view.TreeView$PopupSupport.mouseClicked(TreeView.java:1624)
   at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:253)
   at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:252)
   at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:252)
   at java.awt.AWTEventMulticaster.mouseClicked(AWTEventMulticaster.java:252)
   at java.awt.Component.processMouseEvent(Component.java:6266)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
   at java.awt.Component.processEvent(Component.java:6028)
   at java.awt.Container.processEvent(Container.java:2041)
   at java.awt.Component.dispatchEventImpl(Component.java:4630)
   at java.awt.Container.dispatchEventImpl(Container.java:2099)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4574)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4247)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4168)
   at java.awt.Container.dispatchEventImpl(Container.java:2085)
   at java.awt.Window.dispatchEventImpl(Window.java:2478)
   at java.awt.Component.dispatchEvent(Component.java:4460)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:158)
   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)