4k monitor
Gw2 in fullscreen mode with 25XXpx * 1440px
When i tab out of the game to a different window (alt+tab) and then switch back to the game (which obviously minimized) the ingame resolution is kittened up.
Pretty easy to spot since the point where your mouse is displayed on the screen isnt were it is registered on the game (mouseover effect is your friend).
For me its then displayed 2cm to the left of where it actually should be. Not quite sure if this even is game related or more OS related but I thought id give it a try.
Quickfix is to change the ingame display resolution to anything else and the mouse couror is back where it should be.
Just really annoying since you have to select a different resolution to get the mouse pointer back to a normal position and then select your previous resolution again to be back at the same setting as when you switched out of the game.
If you need any video, screens, more detailed bug report -> gimme a heads up
Cheers
