Using HelloSanity, click on the controls button and try to scroll the image pane. You will immediately see the NPE:

java.lang.NullPointerException
        at com.sun.javafx.sg.prism.NGNode.invalidateCacheByTranslation(NGNode.ja
va:852)
        at com.sun.javafx.sg.prism.NGNode.markDirtyByTranslation(NGNode.java:737
)
        at com.sun.javafx.sg.prism.NGNode.setTransformMatrix(NGNode.java:367)
        at javafx.scene.Node.impl_updatePeer(Node.java:536)
        at javafx.scene.Parent.impl_updatePeer(Parent.java:108)
        at javafx.scene.layout.Region.impl_updatePeer(Region.java:2049)
        at javafx.scene.Node.impl_syncPeer(Node.java:481)
        at javafx.scene.Scene$ScenePulseListener.synchronizeSceneNodes(Scene.jav
a:2195)
        at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2315)
        at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:324)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:53
2)
        at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:51
2)
        at com.sun.javafx.tk.quantum.QuantumToolkit$16.run(QuantumToolkit.java:3
79)
        at com.sun.glass.ui.lens.LensApplication$RunnableEvent.dispatch(LensAppl
ication.java:169)
        at com.sun.glass.ui.lens.LensApplication._runLoop(LensApplication.java:7