java.lang.NullPointerException: Cannot find previous mode named 'collaboration'
        at org.netbeans.core.windows.PersistenceHandler.initPreviousModes(PersistenceHandler.java:365)
        at org.netbeans.core.windows.PersistenceHandler.load(PersistenceHandler.java:206)
        at org.netbeans.core.windows.WindowSystemImpl.load(WindowSystemImpl.java:69)
        at org.netbeans.core.NonGui$3.run(NonGui.java:205)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:461)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:190)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:176)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)