So another odd CS5 behavior going on. When I go from full screen to windowed I sometimes get this full system hang. Photoshop does not crash but it makes the whole computer drag for about a minute. Slow motion typing, can't switch apps, full slow down. Trying to get lucky and have my Activity Monitor running and visible next time it happens. But right now I see two instances of a crash daemon sitting there. I have to quit Photoshop to clear them and quitting Photoshop take a very long time when these are present.
No idea what is going on though.
On a side note, I have not successfully used content aware replace on a image yet. worked on 30 images yesterday for a client. Tried on about 8.