NPE from MessagePassingJSObject via eval()

When running Ensemble as a applet, clicking around samples after a bit it throws the error below. It happens when Ensemble is trying to call into JS to set the browser location to reflect current showing sample. I will add a workaround to Ensemble for now to catch and retry when exception is thrown.


java.lang.NullPointerException
at sun.plugin2.main.client.MessagePassingJSObject.waitForReply(Unknown Source)
at sun.plugin2.main.client.MessagePassingJSObject.eval(Unknown Source)
at ensemble.Ensemble2$15.handle(Ensemble2.java:376)
at ensemble.Ensemble2$15.handle(Ensemble2.java:374)
at com.sun.scenario.animation.shared.TimelineClipCore.visitKeyFrame(Unknown Source)
at com.sun.scenario.animation.shared.TimelineClipCore.playTo(Unknown Source)
at javafx.animation.Timeline.impl_playTo(Unknown Source)
at com.sun.scenario.animation.shared.InfiniteClipEnvelope.timePulse(Unknown Source)
at javafx.animation.Animation.impl_timePulse(Unknown Source)
at com.sun.scenario.animation.shared.AnimationPulseReceiver.timePulse(Unknown Source)
at com.sun.scenario.animation.AbstractMasterTimer.timePulseImpl(Unknown Source)
at com.sun.scenario.animation.AbstractMasterTimer$MainLoop.run(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit$10.run(Unknown Source)
at com.sun.glass.ui.win.WinApplication._enterNestedEventLoop(Native Method)
at com.sun.glass.ui.Application.enterNestedEventLoop(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.enterNestedEventLoop(Unknown Source)
at com.sun.deploy.uitoolkit.impl.fx.FXPluginToolkit$FxWaiter.wait(Unknown Source)

Related: seems to happen when the TreeView stops working:
    Warning failed to get browser location, retrying...
    sun.plugin2.main.client.PluginMain: unrecognized message ID 27