Panel on Screen above other screen does lead to applications not respecting

Submitted by Alexmitter

Assigned to Xfce Bug Triage

Link to original bug (#15306)

Description

This one is hard to explain. I have a weird 4 Screen setup were one screen is above another one. If i place a Panel on the bottom of the upper one, applications do not respect its space and expand under it. If I place it on the top, applications respect it. This only happens with that screen that is above another one.

To explain it better, I made a video: https://youtu.be/Ughn8lp7xuE

Xubuntu 18.04 List of package versions: https://pastebin.com/8wTa1TZy

Version: Unspecified