Linux needs better multi-monitor support. It’s better than it’s ever been, but it’s still janky and giving black screens on tertiary screens at times.
EDIT: It’s funny how the comments are all over the place. “works for me”, “it’s broken on KDE but works on XFCE”, “it’s broken on XFCE but works on KDE”, etc. I think that’s a good sign there are problems with multi-monitor support.