Around a week ago or so, Mission Control became very choppy. I try to do it and it sort sticks and then stutters and then shows all the windows. I've restarted, repaired permissions, verified the disk. I'm on 10.7.5 and I have a mid 2009 MBP 13". It is the only part of the system that is laggy. Minimizing works fine and videos online are smooth. Thanks!