In ubuntu (or perhaps more generally in linux), I have found an unpleasant condition when the mouse or the keyboard contends for direction of the cursor in an emacs window. I think it happens when I go meta with the control key. I found a nice package that I put in my .emacs file which seems to ameliorate this -- https://raw.githubusercontent.com/purcell/disable-mouse/master/disable-mouse.el

😛