When opening CS GO, I always get this gnome pop-up message saying that CS GO is unresponsive, and asking if I want to close the app. Obviously this is not the case, after a few seconds the game loads, but the pop-up message is kinda annoying.

This is the same issue that many source games have. Luckily, it has already been fixed for Dota 2: ValveSoftware/Dota-2#516

So hopefully it should be an easy fix.