java.lang.NullPointerException
        at org.netbeans.modules.editor.NbEditorDocument.createEditor(NbEditorDocument.java:170)
        at org.openide.text.CloneableEditor$DoInitialize.initCustomEditor(CloneableEditor.java:497)
        at org.openide.text.CloneableEditor$DoInitialize.initVisual(CloneableEditor.java:599)
        at org.openide.text.CloneableEditor.getEditorPane(CloneableEditor.java:1067)
        at org.netbeans.core.multiview.MultiViewPeer.getEditorPane(MultiViewPeer.java:507)
        at org.netbeans.core.multiview.MultiViewPeer.isToolbarVisible(MultiViewPeer.java:645)
        at org.netbeans.core.multiview.MultiViewPeer.peerComponentOpened(MultiViewPeer.java:235)
        at org.netbeans.core.multiview.MultiViewCloneableTopComponent.componentOpened(MultiViewCloneableTopComponent.java:139)
Caused: java.lang.IllegalStateException: [Winsys] TopComponent org.netbeans.core.multiview.MultiViewCloneableTopComponent throws exception/error from its componentOpened() method.
Please repair it! Probable cause is at org.netbeans.modules.editor.NbEditorDocument.createEditor(NbEditorDocument.java:170)
        at org.openide.windows.WindowManager.logThrowable(WindowManager.java:363)
        at org.openide.windows.WindowManager.componentOpenNotify(WindowManager.java:302)
        at org.netbeans.core.windows.WindowManagerImpl.notifyTopComponentOpened(WindowManagerImpl.java:972)
        at org.netbeans.core.windows.Central.addModeOpenedTopComponent(Central.java:771)
        at org.netbeans.core.windows.ModeImpl.addOpenedTopComponent(ModeImpl.java:311)
        at org.netbeans.core.windows.PersistenceHandler.initModeFromConfig(PersistenceHandler.java:420)
        at org.netbeans.core.windows.PersistenceHandler.load(PersistenceHandler.java:203)
        at org.netbeans.core.windows.WindowSystemImpl.load(WindowSystemImpl.java:77)
        at org.netbeans.core.NonGui$2.run(NonGui.java:177)
        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:117)
        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)