While running HelloRadioButton, an exception has been thrown when I've exited the toy:

Exception in thread "JavaFX Application Thread" java.lang.IllegalStateException: This operation is permitted on the event thread only; currentThread = JavaFX Application Thread
at com.sun.glass.ui.Application.checkEventThread(Application.java:423)
at com.sun.glass.ui.View.isClosed(View.java:409)
at com.sun.glass.ui.mac.MacTouchInputSupport.notifyNextTouchEvent(MacTouchInputSupport.java:122)
at com.sun.glass.ui.mac.MacGestureSupport.notifyNextTouchEvent(MacGestureSupport.java:77)

Note that I've never seen it before, so this may be an intermittent failure. Please see the stack trace and try to figure out when the calls could occur on the wrong thread. Perhaps they do occur on the right thread, but when exiting the FX/Glass have already nullified the reference to the FX thread, and hence the exception is reported. We need to eliminate the calls occurring too late because they're useless anyway.