So I'm running into this issue where if I alt-tab into fullscreen applications, then click (I'm not sure the exact sequence of events), I lose control of the foreground application. My mouse still moves around. If I have video or audio in the background, it continues to play. However, xkill will not work, and the only way I can regain control is to restart the PC from the reset button. I'm guessing I'm somehow misusing a function of eOS, but I don't know what I can do to avoid it or regain control from it. Can anyone help me out? *update* I've noticed this happens in firefox most when I'm fullscreen in YouTube. I'm wondering if this has something to do with Firefox.