java.lang.NullPointerException
   at org.netbeans.api.visual.model.ObjectScene.setFocusedObject(ObjectScene.java:349)
   at org.uml.visual.widgets.ClassDiagramScene.setFocusedObjectAndToggleListeners(ClassDiagramScene.java:455)
   at org.uml.visual.widgets.ClassDiagramScene.deselectAll(ClassDiagramScene.java:432)
   at org.uml.visual.UMLTopComponent.componentDeactivated(UMLTopComponent.java:154)
   at org.openide.windows.WindowManager.activateComponent(WindowManager.java:279)
   at org.netbeans.core.windows.WindowManagerImpl.notifyRegistryTopComponentActivated(WindowManagerImpl.java:1171)
   at org.netbeans.core.windows.Central.setActiveMode(Central.java:258)
   at org.netbeans.core.windows.Central.userActivatedMode(Central.java:1901)
   at org.netbeans.core.windows.view.DefaultView.userActivatedModeView(DefaultView.java:668)
   at org.netbeans.core.windows.view.ui.TabbedHandler$ActivationManager.handleActivation(TabbedHandler.java:547)
   at org.netbeans.core.windows.view.ui.TabbedHandler$ActivationManager.eventDispatched(TabbedHandler.java:494)
   at java.awt.Toolkit$SelectiveAWTEventListener.eventDispatched(Toolkit.java:2444)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2336)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit$ToolkitEventMulticaster.eventDispatched(Toolkit.java:2335)
   at java.awt.Toolkit.notifyAWTEventListeners(Toolkit.java:2294)
   at java.awt.Component.dispatchEventImpl(Component.java:4768)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Component.dispatchEvent(Component.java:4698)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4832)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4489)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4422)
   at java.awt.Container.dispatchEventImpl(Container.java:2273)
   at java.awt.Window.dispatchEventImpl(Window.java:2719)
   at java.awt.Component.dispatchEvent(Component.java:4698)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:740)
   at java.awt.EventQueue.access$300(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:699)
   at java.awt.EventQueue$3.run(EventQueue.java:697)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
   at java.awt.EventQueue$4.run(EventQueue.java:713)
   at java.awt.EventQueue$4.run(EventQueue.java:711)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:710)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)