Weird "permanent" square shows up on the desktop wallpaper

Hey all,

For some reason, when I change my resolution to something which it normally is (1080). A weird grey box/square appears in my wallpaper and doesn’t go away until I reboot.
See screenshot:



I've tried the following so far:

- Updating graphic card drivers
- Changing wallpapers
- Uninstalling everything related to themeing
- I did a sfc /scannow
- Ran a registery cleaner
- Refeshing on my desktop

I'm at a point that I have no clue anymore what it could be.

Hope someone can share some help.

Thanks for reading

Are you talking about the box around the Unicorn?
What does it look like when you restore the resolution using the same wallpaper?

Almost looks like an image overlaid on the desktop that has not been stretched to full screen size.