Run attached application and click on button in the top of scene.

My output:
run:
Is error? false
ImageView@1d95643
java.lang.NullPointerException
at com.sun.javafx.scene.control.skin.LabeledImpl$1.invalidated(LabeledImpl.java:110)
at com.sun.javafx.binding.ExpressionHelper$SingleInvalidation.fireValueChangedEvent(ExpressionHelper.java:155)
at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:100)
at javafx.beans.property.ObjectPropertyBase.fireValueChangedEvent(ObjectPropertyBase.java:123)
at javafx.beans.property.ObjectPropertyBase.markInvalid(ObjectPropertyBase.java:130)
at javafx.beans.property.ObjectPropertyBase.set(ObjectPropertyBase.java:163)
at javafx.beans.property.ObjectProperty.setValue(ObjectProperty.java:84)
at javafx.scene.control.Labeled.setGraphic(Labeled.java:320)
at menubuttonbug.SplitMenuButtonIssue$2.handle(SplitMenuButtonIssue.java:78)
at menubuttonbug.SplitMenuButtonIssue$2.handle(SplitMenuButtonIssue.java:60)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:2649)
at javafx.scene.Scene$ClickGenerator.access$6200(Scene.java:2583)
at javafx.scene.Scene$MouseHandler.process(Scene.java:2904)
at javafx.scene.Scene$MouseHandler.process(Scene.java:2689)
at javafx.scene.Scene$MouseHandler.access$1300(Scene.java:2655)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1281)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:1913)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:215)
at com.sun.glass.ui.View.handleMouseEvent(View.java:493)
at com.sun.glass.ui.View.notifyMouse(View.java:871)
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$2$1.run(WinApplication.java:62)
at java.lang.Thread.run(Thread.java:722)
Exception in thread "JavaFX Application Thread"

Only for tests analisys purposes, I have to mention: the result - exception in log and image is not shown.