When re-ordering tabs of a TabPane in the Scene builder, I got the following NPE, no Scene Builder code is involved in the exception trace dump.

java.lang.NullPointerException
at com.sun.javafx.scene.control.skin.TabPaneSkin$TabControlButtons$7.handle(TabPaneSkin.java:1530)
at com.sun.javafx.scene.control.skin.TabPaneSkin$TabControlButtons$7.handle(TabPaneSkin.java:1519)
at com.sun.scenario.animation.shared.TimelineClipCore.visitKeyFrame(TimelineClipCore.java:217)
at com.sun.scenario.animation.shared.TimelineClipCore.playTo(TimelineClipCore.java:158)
at javafx.animation.Timeline.impl_playTo(Timeline.java:182)
at com.sun.scenario.animation.shared.SingleLoopClipEnvelope.timePulse(SingleLoopClipEnvelope.java:119)
at javafx.animation.Animation.impl_timePulse(Animation.java:953)
at com.sun.scenario.animation.shared.AnimationPulseReceiver.timePulse(AnimationPulseReceiver.java:117)
at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(AbstractMasterTimer.java:364)
at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(AbstractMasterTimer.java:287)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit.java:455)
at com.sun.javafx.tk.quantum.QuantumToolkit$8.run(QuantumToolkit.java:326)