Playing madden 2011 on my iPhone and the phone warmed up after playing few games and the IS moved while I was playing the game(trying to pass to wr) I use IS on my canon 7d slr with no issue. My IS front cover always moves around when it warms up. My advice is to not buy IS, since moves when it is warm. Going with SGP front cover and keeping IS on the back. I am running white bumper also.