Is this an EXTREME BUG or something not DD related?

Hi!
I guess this isn't Desktop Dungeon related, but something else, but still; I have to ask to be sure.
After playing DD for 10 hours without pause in fullscreen mode I finally exit fullscreen and close DD.
To my horror there now is a (seemingly permanent) imprint/burn/trace of the DD inventory on my monitor. It shows as a transparent non-coloured "raster" kind of imprint, that functions as an overlay on everything else my monitor shows.
Can this in any way be related do DD? Is it even possible for an game to have a bug of that kind? Or is it what I think, that my monitor is malfunctioning (giving permanent traces) OR that my new graphic card (radeon 7750) has caused this to happen, and destroyed my monitor. What is technically possible as reason? Game, Monitor or Graphic card flaw?
Any help in the right direction, even if this probably isn't DD related, is appreciated. Before I know for sure that DD has nothing to do with this - despite my permanent DD trace on my monitor - I won't dare to play DD anymore.
I guess this isn't Desktop Dungeon related, but something else, but still; I have to ask to be sure.
After playing DD for 10 hours without pause in fullscreen mode I finally exit fullscreen and close DD.
To my horror there now is a (seemingly permanent) imprint/burn/trace of the DD inventory on my monitor. It shows as a transparent non-coloured "raster" kind of imprint, that functions as an overlay on everything else my monitor shows.
Can this in any way be related do DD? Is it even possible for an game to have a bug of that kind? Or is it what I think, that my monitor is malfunctioning (giving permanent traces) OR that my new graphic card (radeon 7750) has caused this to happen, and destroyed my monitor. What is technically possible as reason? Game, Monitor or Graphic card flaw?
Any help in the right direction, even if this probably isn't DD related, is appreciated. Before I know for sure that DD has nothing to do with this - despite my permanent DD trace on my monitor - I won't dare to play DD anymore.