ET 2002: java.lang.NullPointerException: <no message>
java.lang.NullPointerException
        at org.openide.explorer.propertysheet.DefaultPropertyModel.propertyChange(DefaultPropertyModel.java:191)
        at org.openide.util.WeakListener$PropertyChange.propertyChange(WeakListener.java:305)
        at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(SwingPropertyChangeSupport.java:161)
        at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(SwingPropertyChangeSupport.java:130)
        at javax.swing.JComponent.firePropertyChange(JComponent.java:3208)
        at javax.swing.JComponent.addNotify(JComponent.java:3501)
        at java.awt.Container.addNotify(Container.java:1579)
        at javax.swing.JComponent.addNotify(JComponent.java:3500)
        at java.awt.Container.addImpl(Container.java:374)
        at javax.swing.JTabbedPane.insertTab(JTabbedPane.java:445)
        at org.netbeans.core.windows.frames.SplitContainerImpl.componentAdded(SplitContainerImpl.java:417)
        at org.netbeans.core.windows.frames.DefaultContainerImpl.addTopComponent(DefaultContainerImpl.java:278)
        at org.netbeans.core.windows.ModeImpl.addToContainer(ModeImpl.java:1780)
        at org.netbeans.core.windows.ModeImpl.access$400(ModeImpl.java:77)
        at org.netbeans.core.windows.ModeImpl$1.performCommand(ModeImpl.java:396)
        at org.netbeans.core.windows.DeferredPerformer.processCommand(DeferredPerformer.java:186)
        at org.netbeans.core.windows.DeferredPerformer.putRequest(DeferredPerformer.java:83)
        at org.netbeans.core.windows.ModeImpl.dockInto(ModeImpl.java:377)
        at org.netbeans.core.windows.ModeImpl.dockInto(ModeImpl.java:357)
        at org.netbeans.core.windows.ModeImpl.dockInto(ModeImpl.java:345)
        at org.netbeans.core.windows.WindowManagerImpl$TopComponentManager.doOpen(WindowManagerImpl.java:1451)
        at org.netbeans.core.windows.WindowManagerImpl$TopComponentManager.access$1100(WindowManagerImpl.java:1316)
        at org.netbeans.core.windows.WindowManagerImpl$4.run(WindowManagerImpl.java:1412)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:154)
[catch] at java.awt.EventQueue.dispatchEvent(EventQueue.java:337)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:131)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:98)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:85)