On screen artefact

When moving any window, not only finder, I get this rectangle artefact on my screen. If I have a second display, it goes there as well. Anyone here facing this issue?

Here is how it looks

Is the link still working? I cannot access it for some reason.

No problem. I’ve uploaded it


This is unlikely caused by TotalFinder. I don’t have any code which would draw something like that.

Thanks! Will dig further )