NPE in MenuButtonSkin addAccelerators method.

It try to access menuParent field of menuItem which is Null, if item added to MenuButton directly.

{code}
CheckMenuItem gridSnap = new CheckMenuItem("snap to grid");
            gridSnap.setSelected(frame.isSnapToGrid());
            gridSnap.setOnAction(new EventHandler<ActionEvent>() {
                @Override
                public void handle(ActionEvent actionEvent) {
                    ...
                }
            });

gridSnap.setAccelerator(KeyCombination.keyCombination("Ctrl+Shift+G"));

MenuButton mb = new MenuButton();
mb.getItems().add(gridSnap);
{code}


java.lang.NullPointerException
at com.sun.javafx.scene.control.skin.MenuButtonSkinBase$5.run(MenuButtonSkinBase.java:306)
at com.sun.javafx.scene.KeyboardShortcutsHandler.processAccelerators(KeyboardShortcutsHandler.java:296)
at com.sun.javafx.scene.KeyboardShortcutsHandler.dispatchBubblingEvent(KeyboardShortcutsHandler.java:119)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Scene$KeyHandler.process(Scene.java:3509)
at javafx.scene.Scene$KeyHandler.access$2300(Scene.java:3468)
at javafx.scene.Scene.impl_processKeyEvent(Scene.java:1900)
at javafx.scene.Scene$ScenePeerListener.keyEvent(Scene.java:2266)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleKeyEvent(GlassViewEventHandler.java:127)
at com.sun.glass.ui.View.handleKeyEvent(View.java:518)
at com.sun.glass.ui.View.notifyKey(View.java:951)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.access$100(WinApplication.java:29)
at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.java:73)
at java.lang.Thread.run(Thread.java:662)