java.lang.AssertionError: ContextAwareAction cannot return null: org.netbeans.modules.uml.drawingarea.actions.SelectAllAction@4d37fb09
        at org.openide.windows.TopComponent.processKeyBinding(TopComponent.java:1028)
        at javax.swing.JComponent.processKeyBindings(JComponent.java:2895)
        at javax.swing.JComponent.processKeyEvent(JComponent.java:2812)
        at java.awt.Component.processEvent(Component.java:6078)
        at java.awt.Container.processEvent(Container.java:2085)
        at java.awt.Component.dispatchEventImpl(Component.java:4667)
        at java.awt.Container.dispatchEventImpl(Container.java:2143)
        at java.awt.Component.dispatchEvent(Component.java:4497)
        at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1848)
        at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:704)
        at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:969)
        at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:841)
        at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:668)
        at java.awt.Component.dispatchEventImpl(Component.java:4539)
        at java.awt.Container.dispatchEventImpl(Container.java:2143)
        at java.awt.Window.dispatchEventImpl(Window.java:2475)
        at java.awt.Component.dispatchEvent(Component.java:4497)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:635)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)