SUMMARY See screenshot. The title should either have the same background as the rest of the window or the area with the different color should extend to the edge
Created attachment 135021 [details] Screenshot
This is a regression compared to 5.20
Can confirm on Plasma 5.20.80 in Neon Unstable Edition.
*** Bug 432092 has been marked as a duplicate of this bug. ***
Looked into this a bit and IMO it doesn't seem like a Junior Job. :) The problem is that KPageDialog adds its own margins here. We can't easily remove them without breaking other QWidgets-based dialogs that expect them. What we probably need to do is make a new face type that has zero margins around the whole content item, but margins around the button box sub-component. There is also a right margin that is appearing on the right side that I hven't tracked down yet. Once we fix all of that, we'd adjust KCMshell to set specify the use of the new face type. I'll see if I can get it done.
Or actually, an arg might make more sense than a new face type, since in principle you might want the "no margins" look for any existing face type.
Or perhaps there's an even easier way...
...Not actually so easy after all. For reference, https://invent.kde.org/frameworks/kwidgetsaddons/-/merge_requests/15 was a previous attempt to fix this that got stuck due to disagreements on the size of the margins for non-touching use cases.
A possibly relevant merge request was started @ https://invent.kde.org/frameworks/kcmutils/-/merge_requests/36
Git commit 5a5718b22a396d392df8241ef6e98b8b6faca009 by Ismael Asensio. Committed on 11/02/2021 at 18:17. Pushed by iasensio into branch 'master'. Fix wrong margins on QML-based KCMs Previous layouting relied on the page GridLayout's spacing and global contents margins to set components spatially. This breaks for Qml-based KCMs, as the Qml component sets its own internal title, spacing and margins. Now, we remove the contents margins on Qml-based KCMs so the can expand to the edges, but keep them on QtWidget ones, so they remain visually unchanged. This enforces consistency between different standalone KCMs, systemsettings sidebar view and systemsettings icon view. It also removes an ugly extra pixel margin on the right side caused by the GridLayout spacing. Co-Authored by: ngraham FIXED-IN: 5.80 M +5 -1 src/kcmoduleproxy.cpp M +3 -2 src/kcmoduleqml.cpp M +22 -2 src/kcmultidialog.cpp https://invent.kde.org/frameworks/kcmutils/commit/5a5718b22a396d392df8241ef6e98b8b6faca009