With T10028 closed there is still some more work:
* KScreen KCM is half QML and half QWidgets. Port everything to QML. ~~--> sebas branch available~~ T11217
* Make the KCM mobile-ready. --> very low priority
* On Wayland scale should be controlled by a slider on non-integer values. --> First fix some remaining KWin issues with fractional scaling (see bugs reports).
* In D16997 a control for output retention is added to the KCM. Two follow-up tasks are to be discussed:
* No retention setting per output, but instead per config (just iterate over the control of all outputs and set to the same value)
* Reword the setting.
* Remember in control file, if a submitted resolution or frame rate is manually set or an automatically determined value and:
* Show this in KCM.
* React in daemon accordingly.
* Fix random Plasmashell crashes and panel positioning in multi-screen setups.
* Look into laptop-lid opened/closed configurations working correctly (see D21082).
* Real output duplication, not just moving. --> Either via black bars or stretching/cropping (only till certain threshold?), fix display identification in this case.
* Primary screen: specified in KScreen, plasmashell needs to know (d-bus?)