Wrong wallpaper used on lock screen when Xfdesktop is built with alternative default backdrop
The default Xubuntu wallpaper is not used for the Xfce Screensaver lockscreen.
This is related to https://bugs.launchpad.net/ubuntu/+source/xfdesktop4/+bug/2092806
Steps to reproduce:
- Create a new user profile or install Xubuntu 25.04.
- Do not change the user's wallpaper.
- Lock the screen.
Expected results:
The default Xubuntu wallpaper and the one the user shows in the current session is displayed in the background.
Actual results:
The default Xfce wallpaper is displayed in the background.
Cause:
Xfdesktop 4.20 changed how distributors set the default wallpaper. In previous releases, this was done by setting default monitor settings that would automatically be picked up by Xfdesktop is loaded on a fresh user profile. The new process involves a build-time flag.
Xfdesktop 4.18: https://github.com/Xubuntu/xubuntu-default-settings/blob/oracular/etc/xdg/xdg-xubuntu/xfce4/xfconf/xfce-perchannel-xml/xfce4-desktop.xml#L18
Xfdesktop 4.20 (configure flag):
--with-default-backdrop-filename=/usr/share/xfce4/backdrops/xubuntu-wallpaper.pngThe previous behavior allowed either /last-image or /image-path to be set. By setting defaults at build time, these Xfconf properties are not pre-set and therefore cannot be read by xfce4-screensaver (see below line for reference).
Recommendation:
Xfdesktop should provide a mechanism to query the default or per-monitor wallpaper, and Xfce Screensaver use that instead of hardcoded values. This impacts distributions shipping customized versions of Xfce.
References:
Related (xfdesktop4): xfce/xfdesktop#364 (closed)
Downstream reports:
Activity
So if I understand correctly there is no way to fix this in the current state of xfdesktop? It would depend on feature request xfce/xfdesktop#364 (closed) that @kelnos refuses to address? From there I'm not sure what we can do here. Isn't there a workaround? For example, can't Xubuntu set the xfdesktop xfconf channel properties that were previously defined in a post-install script?
added 3. Need Info label