In some cases the display does not show a background in the "customize theme" at all. When you do specify a background for the theme, it does not appear to have any effect, either in the "customize theme" window or in the actual login window. Reproducible: Always Steps to Reproduce: 1. Go into SDDM 2. Select a Background in "Customize theme" 3. Apply the Change (Requires Authentication). Actual Results: Nothing changes Expected Results: I expect to see the new background displayed in the preview window as well as during the login process. I should note that this is in KDE 5.9.0, which does not seem to be available in the version dropdown here.
Sorry, it is 5.2.2.
*** This bug has been marked as a duplicate of bug 344867 ***