Maximize sets hight only to a half of the 4k external screen after restarting plasma shell with `killall plasmashell` and `plasmashell`.
STEPS TO REPRODUCE
1. `killall plasmashell`
3. Press maximize button on a window
The height is only half of the external 4k screen. On the laptop screen (1080p), the maximization works fine.
The height should stretch over the whole screen size
Operating System: Kubuntu 20.04
KDE Plasma Version: 5.18.4
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8
Kernel Version: 5.4.0-29-generic
OS Type: 64-bit
Processors: 12 × Intel® Core™ i7-9850H CPU @ 2.60GHz
Memory: 15,5 GiB of RAM
Graphic card: NVIDIA Quadro P200
Created attachment 128319 [details]
Bug like this are inevitable on X11 because you are using an unsupported mixed screen DPI setup. Those are only supported on Wayland.
See Bug 414866.