After starting the game and waiting for it to be fully loaded I can't alt-tab out of the game and back in as that causes the game to not respond to mouse clicks - unless I'm already in a mission, in those cases I can fire my gun but can't operate any menu/the map
This happens on a amdgpu-radeonsi system with Gnome3/Gnome-shell and a dual-monitor setup where the game has to be moved to the correct screen by hand.