Changing the wallpaper in the kcm_sddm does not change to wallpaper of sddm. Reproducible: Always Steps to Reproduce: 1. Open kcm_sddm 2. Change the wallpaper 3. Hit apply 4. Reboot, restart sddm or whatever - the background doesn't change Actual Results: kcm_sddm shows the correct wallpaper, but sddm seems to ignore it.
I can reproduce this on my system: Arch Linux, kernel 4.2.5-1, x86_64, Plasma 5.4.3, KDE Applications 15.08.3 and KDE Frameworks 15.16. This functionality used to work in older Plasma/KDE Applications versions but has always been very glitchy - I had to try several times before the change was saved and it also used to freeze the entire System Settings from time to time when trying to change the background.
*** This bug has been marked as a duplicate of bug 370521 ***