See the attached screenshots and pictures for actual results. My steps are: 1. Go to systemsettings -> kscreen settings 2. Switch DVI-I monitor off and press "Apply". - Result: Screenshot 1, nothing had happened 3. Switch DVI-I and HDMI monitor off and press "Apply". - Result: Screenshot 2, Picture 2, strange duplicating of the toolbar. 4. Switch DVI-I and HDMI on and off again and press "Apply". - Result: Screenshot 3, Picture 3 It has to be noted, that only the picture is moved. The actually mouse interaction remains at the same positions as before. (i.e. you click with the mouse on the upper left of the screen and the k-menu pops up in the middle of the screen). I'm using Gentoo with Plasma 5.9.3, Qt 5.7.1, Wayland session started with SDDM and use of OpenRC and elogind. This bug is reproducible. If you need other information, please say so.
Created attachment 104659 [details] Picture 2
Created attachment 104660 [details] Picture 3
Created attachment 104661 [details] Screenshot 1
Created attachment 104662 [details] Screenshot 2
Created attachment 104663 [details] Screenshot 3
I have the same issue, on Arch Linux (Plasma 5.10.3, frameworks 5.35.0, Qt 5.9.0): when disabling my laptop screen and making the external (VGA) screen the main output, the laptop screen does not turn off, but shows the same output as the external screen (for the part that is visible on the smaller screen). Please let me know if more information is needed.
Same on Kubuntu 17.10 with plasma 5.11 I have an external monitor and the built in Monitor (Notebook) Can't deativate the notebook monitor, the inbuilt monitor stays on, and is in "extended" mode.
Works fine for me with current master (~Plasma 5.17)
This is fixed now.