xfdesktop "assign icon layout" dialog appears again and again

Issue Description

I a Laptop and another computer connected to a TV screen. Most times, the TV is off, and I use both connected computers mostly via remote desktop. Just sometimes I use the local display. Both run the latest version of XFCE on Arch Linux, but the issue only occurs on the Laptop. I assume it's because the Laptop has it's own screen, and the other computer doesn't.
When I switch the TV on and off or switch between inputs, it looks like every time there is an additional instance of the dialog asking about applying the icon layout. I already tried checking the "always ..." checkbox, but it still reoccurs.
What makes this even worse is that every new instance appears below all other windows and also all other existing instances.

xfdesktop_assign_icon_layout

Steps to Reproduce Issue

  • Connect a Laptop to an external screen with multiple inputs
  • Choose "External screen only" in the dialog that appears
  • Connect a second computer
  • Switch between inputs, and/or switch the external monitor on and off while the Laptop lid is closed.

see above

Expected Behavior

This dialog should appear only once, and either on top of all windows or in "same as other windows" mode.

I think that two things would help:

  • Ensure the "Always ..." checkbox is remembered.
  • Check if the dialog is already open before opening it, so even without "Always ..." it opens only once.

Additional Information

I'm not 100% sure if the difference is because the Laptop has it's own screen or if there is a setting I unknowingly changed.

Environment & Versions

  • OS distribution and version: Arch Linux
  • Overall Xfce version: 4.20
  • xfdesktop version (git hash if not a release): 4.20.2-1
  • thunar version (if issue related to file/launcher icons): 4.20.10-1
  • Windowing system (X11/Wayland): X11
  • Compositor and version (if Wayland): N/A
  • GTK Theme: Adwaita
  • Icon Theme: elementary Xfce dark
  • UI Scale Factor: 100%
Edited by Markus Näher