Long press on virtual keyboard key causes NPE

Long press on a virtual keyboard key to bring up a secondary keyboard to choose additional characters causes NPE:

java.lang.NullPointerException
        at com.sun.javafx.scene.control.skin.FXVKSkin.layoutChildren(FXVKSkin.ja
va:466)
        at javafx.scene.control.Control.layoutChildren(Control.java:564)
        at javafx.scene.Parent.layout(Parent.java:1052)
        at javafx.scene.Parent.layout(Parent.java:1058)
        at javafx.scene.Group.impl_computeLayoutBounds(Group.java:159)
        at javafx.scene.Node$15.computeBounds(Node.java:3126)
        at javafx.scene.Node$LazyBoundsProperty.get(Node.java:8787)
        at javafx.scene.Node$LazyBoundsProperty.get(Node.java:8757)
        at javafx.scene.Node.getLayoutBounds(Node.java:3141)
        at javafx.stage.PopupWindow.syncWithRootBounds(PopupWindow.java:478)
        at javafx.stage.PopupWindow.access$000(PopupWindow.java:91)
        at javafx.stage.PopupWindow$1.invalidated(PopupWindow.java:106)
        at com.sun.javafx.binding.ExpressionHelper$SingleInvalidation.fireValueChangedEvent(ExpressionHelper.java:135)
        at com.sun.javafx.binding.ExpressionHelper.fireValueChangedEvent(ExpressionHelper.java:80)
        at javafx.scene.Node$LazyBoundsProperty.invalidate(Node.java:8797)
        at javafx.scene.Node.impl_layoutBoundsChanged(Node.java:3296)
        at javafx.scene.Node.impl_notifyLayoutBoundsChanged(Node.java:3696)
        at javafx.scene.Node.impl_geomChanged(Node.java:3648)
        at javafx.scene.Parent$1.onChanged(Parent.java:351)
        at com.sun.javafx.collections.TrackableObservableList$1.onChanged(TrackableObservableList.java:48)
        at com.sun.javafx.collections.ListListenerHelper$Generic.fireValueChangedEvent(ListListenerHelper.java:315)
        at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:72)
        at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
        at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
        at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
        at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
        at javafx.collections.ModifiableObservableListBase.add(ModifiableObservableListBase.java:155)
        at java.util.AbstractList.add(Unknown Source)
        at com.sun.javafx.collections.VetoableListDecorator.add(VetoableListDecorator.java:200)
        at com.sun.javafx.scene.control.skin.FXVKSkin.showSecondaryVK(FXVKSkin.java:723)
        at com.sun.javafx.scene.control.skin.FXVKSkin.access$600(FXVKSkin.java:69)
        at com.sun.javafx.scene.control.skin.FXVKSkin$3.handle(FXVKSkin.java:254)
        at com.sun.javafx.scene.control.skin.FXVKSkin$3.handle(FXVKSkin.java:251)
        at com.sun.scenario.animation.shared.TimelineClipCore.visitKeyFrame(TimelineClipCore.java:231)
        at com.sun.scenario.animation.shared.TimelineClipCore.playTo(TimelineClipCore.java:172)
        at javafx.animation.Timeline.impl_playTo(Timeline.java:161)
        at javafx.animation.AnimationAccessorImpl.playTo(AnimationAccessorImpl.java:39)
        at com.sun.scenario.animation.shared.SingleLoopClipEnvelope.timePulse(SingleLoopClipEnvelope.java:99)
        at javafx.animation.Animation.impl_timePulse(Animation.java:1084)
        at javafx.animation.Animation$1.timePulse(Animation.java:168)
        at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:344)
        at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(AbstractMasterTimer.java:267)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:474)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:458)
        at com.sun.javafx.tk.quantum.QuantumToolkit$13.run(QuantumToolkit.java:325)
        at com.sun.glass.ui.lens.LensApplication$RunnableEvent.dispatch(LensApplication.java:169)
        at com.sun.glass.ui.lens.LensApplication._runLoop(LensApplication.java:756)
        at com.sun.glass.ui.lens.LensApplication.access$700(LensApplication.java:55)
        at com.sun.glass.ui.lens.LensApplication$4.run(LensApplication.java:815)
        at java.lang.Thread.run(Unknown Source)