A grey square (overlay) in the middle of the screen, Ubuntu 16.04 Dell xps 13 9360 [closed]
I've this grey/black squarein the middle of my screen, when I change working spaces it follows.
and here
Solution 1:
Ok, it was my fault.
The overlay was caused by gnome-screenshot still running in background after a screencap was made.
Problem is solved closing all istances of gnome-screenshot