Wrong wallpaper used on lock screen

[Sean Davis]

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:

1. Create a new user profile or install Xubuntu 25.04.
2. *Do not* change the user's wallpaper.
3. 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.

The 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 read by xfce4-screensaver (see below line for reference).

https://gitlab.xfce.org/apps/xfce4-screensaver/-/blob/master/src/xfce-bg.c?ref_type=heads#L457

ProblemType: Bug
DistroRelease: Ubuntu 25.04
Package: xfce4-screensaver 4.18.4-1
ProcVersionSignature: Ubuntu 6.14.0-15.15-generic 6.14.0
Uname: Linux 6.14.0-15-generic x86_64
ApportVersion: 2.32.0-0ubuntu5
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: XFCE
Date: Sat Apr 12 06:18:04 2025
InstallationDate: Installed on 2025-04-11 (0 days ago)
InstallationMedia: Xubuntu 25.04 "Plucky Puffin" - Daily amd64 (20250411)
ProcEnviron:
 LANG=en_US.UTF-8
 PATH=(custom, no user)
 SHELL=/bin/bash
 TERM=xterm-256color
 XDG_RUNTIME_DIR=<set>
SourcePackage: xfce4-screensaver
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/2107239

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.