You cannot add org.netbeans.modules.refactoring.spi.impl.WhereUsedAction directly to a JMenu etc.; use org.openide.awt.Actions.connect instead
Caused: java.lang.NullPointerException
   at org.netbeans.modules.css.refactoring.CssActionsImplementationProvider$5.run(CssActionsImplementationProvider.java:208)
   at org.openide.util.Mutex.doEvent(Mutex.java:1356)
   at org.openide.util.Mutex.readAccess(Mutex.java:355)
   at org.netbeans.modules.css.refactoring.CssActionsImplementationProvider.isRefactorableEditorElement(CssActionsImplementationProvider.java:198)
   at org.netbeans.modules.css.refactoring.CssActionsImplementationProvider.canFindUsages(CssActionsImplementationProvider.java:152)
   at org.netbeans.modules.refactoring.api.impl.ActionsImplementationFactory.canFindUsages(ActionsImplementationFactory.java:100)
   at org.netbeans.modules.refactoring.spi.impl.WhereUsedAction.enable(WhereUsedAction.java:92)
   at org.netbeans.modules.refactoring.spi.impl.RefactoringGlobalAction$ContextAction.isEnabled(RefactoringGlobalAction.java:182)
   at org.openide.awt.Actions$MenuBridge.updateState(Actions.java:1234)
   at org.openide.awt.Actions$Bridge.propertyChange(Actions.java:932)
   at org.openide.util.WeakListenerImpl$PropertyChange.propertyChange(WeakListenerImpl.java:197)
   at java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:0)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:0)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:0)
   at org.openide.util.SharedClassObject.firePropertyChange(SharedClassObject.java:471)
   at org.openide.util.actions.NodeAction.maybeFireEnabledChange(NodeAction.java:374)
   at org.openide.util.actions.NodeAction$NodesL$1.run(NodeAction.java:526)
   at org.openide.util.Mutex.doEvent(Mutex.java:1356)
   at org.openide.util.Mutex.readAccess(Mutex.java:355)
   at org.openide.util.actions.NodeAction$NodesL.forget(NodeAction.java:524)
   at org.openide.util.actions.NodeAction$NodesL.update(NodeAction.java:493)
   at org.openide.util.actions.NodeAction$NodesL.resultChanged(NodeAction.java:486)
   at org.openide.util.lookup.SimpleProxyLookup.checkLookup(SimpleProxyLookup.java:114)
   at org.openide.util.lookup.SimpleProxyLookup.lookup(SimpleProxyLookup.java:156)
   at org.netbeans.modules.openide.windows.GlobalActionContextImpl.blickActionMapImpl(GlobalActionContextImpl.java:130)
   at org.netbeans.modules.openide.windows.GlobalActionContextImpl.blickActionMap(GlobalActionContextImpl.java:106)
   at org.netbeans.modules.openide.windows.GlobalActionContextImpl.propertyChange(GlobalActionContextImpl.java:200)
   at java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:0)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:0)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:0)
   at java.awt.KeyboardFocusManager.firePropertyChange(KeyboardFocusManager.java:0)
   at java.awt.KeyboardFocusManager.setGlobalPermanentFocusOwner(KeyboardFocusManager.java:0)
   at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:0)
   at java.awt.Component.dispatchEventImpl(Component.java:0)
   at java.awt.Container.dispatchEventImpl(Container.java:0)
   at java.awt.Component.dispatchEvent(Component.java:0)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:0)
   at java.awt.EventQueue.access$500(EventQueue.java:0)
   at java.awt.EventQueue$3.run(EventQueue.java:0)
   at java.awt.EventQueue$3.run(EventQueue.java:0)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:0)
   at java.awt.EventQueue$4.run(EventQueue.java:0)
   at java.awt.EventQueue$4.run(EventQueue.java:0)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:0)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:0)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:0)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:0)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:0)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:0)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:0)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:0)