I'll add support to this. I get same problem through Steam and clearing cache and stuff does nothign at all. And no I can't psot anything either. The file uploads but the window remains. I'd post a screneshot of how it looks but you know, can't... :P
Oh, also, replying to this topic and trying to add a pic don't work either.
Screenshot of how it looks. Basically can click all you like on buttons but only the X to clsoe window has any effect.
https://prnt.sc/fe8o6n