"at-startup" mode unconditionally changes wallpaper once on selection.

Issue Description

Wallpaper changes once after roughly 2 seconds on using change background mode "at startup"

Steps to Reproduce Issue

Wallpaper changes once after roughly 2 seconds on using change background mode "at startup"

  1. Use any resolution.
  2. Set wallpaper folder to something with multiple images.
  3. Turn on change wallpaper.
  4. Select change mode to "at startup"
  5. Wait 1 second.
  6. Wallpaper should automatically be changed without doing right click > next background. This happens only ONCE after selecting "at startup".
  7. Select any other change mode.
  8. Select "at startup"
  9. Wait 1 second, wallpaper changes automatically again. Once only, not more than once.

Expected Behavior

One time wallpaper change with "at startup" mode:

  1. No change in wallpaper should occur on switching to this mode alone.
  2. Change in wallpaper must occur on startup

Environment & Versions

  • OS distribution and version: Debian 13 Trixie amd64
  • Overall Xfce version: xfce4/stable,stable,now 4.20.1 all [Packged by debian]
  • xfdesktop version (git hash if not a release):xfdesktop version 4.20.1-dev- 90a6ae3e, running on Xfce 4.20
  • thunar version (if issue related to file/launcher icons): No issues but 4.20.2
  • Windowing system (X11/Wayland): X11
  • Compositor and version (if Wayland): X11, xfwm4
  • GTK Theme: McOS-XFCE-Edition-II-1 [changes gtk3, gtk2, xfwm4, xfce4-notifyd]
  • Icon Theme: GNOME [Default Provided icon set in debian xfce]
  • UI Scale Factor: 1
  • DPI: unchanged default 95

Extra notes:

To compile and use xfdesktop from scratch, I had to also compile the following packages:

libxfce4ui

libxfce4windowing

xfdektop itself

Current items in /usr/local/bin:

aashu@debian:/usr/local/ bin$ ls iriunwebcam xfce4-about xfce-open xfdesktop-settings ryzenadj xfce-desktop-item-edit xfdesktop Xrain