If a JavaFX program crashes on Mac OS X 10.7 (Lion), the next attempt to run a JavaFX program on Lion will bring up a dialog that says: "The application "Java" quit unexpectedly". You must dismiss the dialog before the app will receive keyboard events. With a full-screen app like "HelloFullscreen" this causes a problem since the app obscures the dialog. Fortunately, the ESC key can still be used to exit full screen mode. There may not be anything we can (or should) do about this since it seems like a Lion "feature".