I've just downgraded Compiz as Timo suggested in https://bugs.launchpad.net/ubuntu/+source/compiz/+bug/760814/comments/84 and everything works so great finally!
I've just downgraded Compiz as Timo suggested in https:/ /bugs.launchpad .net/ubuntu/ +source/ compiz/ +bug/760814/ comments/ 84 and everything works so great finally!