When this happens, could you try to press Ctrl+Alt+T, to open a terminal move the mouse over (it seems enough to get the focus on it), and run on that "unity" (or compiz --replace) ?
When this happens, could you try to press Ctrl+Alt+T, to open a terminal move the mouse over (it seems enough to get the focus on it), and run on that "unity" (or compiz --replace) ?