I started the DX11 version of the game and wanted to alt-tab out, when I'd alt tab out I'd see a flash of the desktop then immediately go back into the game. I tried it several times before giving up.
I wound up closing the game to make the display setting change I needed to (going from duplicating on both monitors to only displaying on one) then got sidetracked and never got to see if changing it back to single monitor fixed the issue.
Wiley.