Created attachment 104987 [details] The attachment shows the activity and part of the default background. As can be seen, the activity is listed with a black background. In the Activities list (Meta+Q), new activities are shown with a black background although the desktop wallpaper is the default wallpaper. Changing the wallpaper to any other picture (or even selecting the default) fixes the issue. Considering that the default wallpaper is not listed as selected when changing it for the first time makes it seem likely that the wallpaper is not properly registered in both the Desktop settings and Activities view. I am running vanilla Ubuntu with KDE Plasma 5.8.5 from the backports PPA by installing kubuntu-desktop.
Can confirm this bug in: Distribution: KDE neon Developer Edition Unstable Branches KDE Plasma Version: 5.10.90 KDE Frameworks Version: 5.37.0 Qt Version: 5.9.1 Kernel Version: 4.10.0-32-generic
Confirmed. If the wallpaper is not changed, but left to be the default one, the configuration file will not contain any info about it and the switcher will not be able to load it.
I can still confirm it on Operating System: Manjaro Linux KDE Plasma Version: 5.19.3 KDE Frameworks Version: 5.73.0 Qt Version: 5.15.0 Creating a new activity results in having a black background / no wallpaper for it by default.
Same bug on Plasma 5.26 Operating System: KDE neon 5.26 KDE Plasma Version: 5.26.0 KDE Frameworks Version: 5.98.0 Qt Version: 5.15.6
I confirm this on current git-master
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/3218
*** Bug 518519 has been marked as a duplicate of this bug. ***
Git commit 3d1febd3813b4fe0fdf8f958e6ff4a6f433dfd21 by Nicolas Fella. Committed on 08/09/2026 at 09:54. Pushed by nicolasfella into branch 'master'. [activitymananger] Fix activity background image The code looks into the appletsrc file to load the wallpaper for a given activity. However that only worked when a custom image was specified by full path. When any of the built-in wallpapers is used the Image key instead points to the wallpaper package folder, not any specific image. Also when the default wallpaper is used the key is empty. Fix all of these cases by selecting one image when given a folder, and fall back to the default wallpaper (called Next) when no config is present. Also when using a color background use the actual default color instead of black M +73 -8 imports/activitymanager/sortedactivitiesmodel.cpp https://invent.kde.org/plasma/plasma-desktop/-/commit/3d1febd3813b4fe0fdf8f958e6ff4a6f433dfd21
Thank you, Nicolas! ♥