Using an LG34950F monitor set to default resolution of 3440x1440.  Playing in full screen mode.  When I go to the options screen to adjust graphics setting etc there does not appear to be any way of leaving the options screen.  Subsequently realized that if I change the resolution to 2560x1440 then I do get the full screen showing allowing selection of the "Done" button.  Not a major bug but more that the game doesn't cater for the native resolution of my monitor as so was frustrating when I couldn't exit the options screen.  Thought I'd report it.