A blocking grey (command?) box on top of the screen

I get this line relatively often, i think this is because i click away from the game on the notification that appears. Nonetheless, i cant hide that line and i cant click on anything and the only way to get rid of it is to restart the game. I also somehow managed to stack 2 boxed when i clicked away second time lmao.
Anyway if someone knows what the hell is it and how to close it, please tell me.
EDIT: also this is very convenient i cant post a screenshot here.