first: sry 4 my bad english.. the german forum is currently not avaiable ... but i need help!

My problem:
I want to create a java application for "League of Legends" ...
if i set "frame.setAlwaysOnTop(true)" .. the frame is on my desktop always on top, but if the game starts (Game is in fullscreen-mode) it is in the background!

Thx :)