I've seen the following error a handful of times in 8b105. Unfortunately it's not consistently reproducible, and I have no idea what caused it (aside from happening when clicking on the UI...I think).

[error] java.lang.NullPointerException
[error] at javafx.scene.Scene$ScenePulseListener.synchronizeScenePropert
ies(Scene.java:2229)
[error] at javafx.scene.Scene$ScenePulseListener.pulse(Scene.java:2321)
[error] at com.sun.javafx.tk.Toolkit.firePulse(Toolkit.java:329)
[error] at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit
.java:479)
[error] at com.sun.javafx.tk.quantum.QuantumToolkit.pulse(QuantumToolkit
.java:459)
[error] at com.sun.javafx.tk.quantum.QuantumToolkit$13.run(QuantumToolki
t.java:326)
[error] at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLater
Dispatcher.java:95)
[error] at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
[error] at com.sun.glass.ui.win.WinApplication.access$300(WinApplication
.java:39)
[error] at com.sun.glass.ui.win.WinApplication$3$1.run(WinApplication.ja
va:101)
[error] at java.lang.Thread.run(Thread.java:724)