Using 1.7, webstart stops sending updates to custom preloader splashscreen, which leaves the GUI still running when the main app is displayed.
You can see the problem if you click the button on this page:
http://mtlvm019.ca.oracle.com/CONFJAVAFX_MAIN/mergeddist/confjava.html
You can see the problem if you click the button on this page:
http://mtlvm019.ca.oracle.com/CONFJAVAFX_MAIN/mergeddist/confjava.html