This is related to compiz. I had my "Move Window" setting set to Alt + Button1 (Left Click). I accidently changed my "Resize Window" setting to the same thing. When I did this, compiz changed my "Move Window" setting to just Button1. This was incredibly annoying to fix because every time I tried to click nothing happened, it would just keep trying to move windows.
Basically, I don't think anything should be changed to Button1. Does this sound reasonable?
Bookmarks