Is there a solution to this problem? I am facing a similar issue. When I press cmd+arrow my AE window changes size and moves to different area of my screen. See screen shot below. So I can't advance one frame at a time. This only happens on my laptop, a Macbook Pro. This is After Effect CS6 version 126.96.36.199. Is there some kind of key re-allocation thing i need to do? Any help with this would be great! Thanks.