Welcome to LG KM555 Forum!
i hope i can help1- open the jar file on your pc with winrar 2- go to the folder META-INF3- open the file MANIFEST.ME using any editor4-ADD THIS LINE TO IT : " MIDlet-Touch-Support: true " (WITHOUT QUOTES )(in the first line for example)5- save the file by pressing Ctlr +S on your keyboard then winrar asks you update archive you say yes and here you go you just made your app full screen.6- enjoy.