Operating System: Windows 7 Ultimate 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_ldr.120503-2030)
I have been encountering an issue where a black windows pops up infront of the game (note: it is still ingame, just over everything else).
I have been trying to recreate it but sadly with no luck.
It might be linked to using ctrl + some key
If this is possibly not a bug, I need to know the key combination I keep using to make this annoying window appear

Inserting screenshot.

Please let me know if you need additional information.