Message box error

[haphazardjoy]

I was just going to assign a hero to an outpost that was near the edge of my play screen. When I released the button I had a message box pop-up, perhaps to say cards need to be assigned to an area on the map, assuming perhaps I overshot and went off window. However, the box that popped up was blank and so had no message nor buttons to confirm, and it didn't respond to me pressing enter. So beyond that being an issue, since the pop-up was there, I couldn't access the menu and had to Ctrl-Alt-Delete out of the game.

[mawna]

Same error, think I was clicking on a free tile(perhaps dragging my pointer) and suddenly a blank box appeared and then it was "No way out"
Ironman mode. Windowed.
edit:Happened again when I was putting my Razor in HQ. It's clearly the message OP was talking about. Also, when I was using a "Defence Training +1"card on a Skullcrusher. It happens when I drop a card in the wrong location.