It's getting me crazy!
compiz or unity refresh screen (like I run
compiz --replace or
unity --replace) by every movement I do (e.g
w) and somehow unexpectedly! sometimes it failed to reload title bar and keyboard functions like
F2 stop working, and I had no chance but reboot!
Sometimes it work without any problem. I couldn't found any reason why this happen.
I wanted to report a bug but I don't have enough information about it.