When changing the screen resolution using kscreen, a maximized panel does not adapt to the full screen width (height not tested, probably affected the same way). A restart of plasmashell fixes this. Reproducible: Always Steps to Reproduce: 1. Start plasma with empty config 2. Change width of primary screen using kscreen The panel now either does not span the whole width of the screen or is wider than the screen. After "kquitapp5 plasmashell; plasmashell" the panel spans the whole screen again. Using unstable Qt 5.7.1.
This should be fixed now, please reopen if not.