When FX.exit() is called it does not completely dispose of the running Applet in a browser. The JavaFX Script runtime continues to execute after the FX.exit() code completes, this means that Timeline continue to run and any graphics content is displayed and updated. The contents of the Browser based stage remain visible which might confuse the user that the script is still executing even though they have
press an Exit or close button on the JavaFX Script's Stage Contents.