I experience a lot of bugs in KScreen in Plasma 5.4.2 in Manjaro Linux, that makes it practically unusable.

I experience all these bugs:
https://bugs.kde.org/show_bug.cgi?id=346961
https://bugs.kde.org/show_bug.cgi?id=344328
https://bugs.kde.org/show_bug.cgi?id=346535
https://bugs.kde.org/show_bug.cgi?id=345225
- Lack of "favorite screen" option that allows to move the panel in the main screen (together with the fact that if I put the panel in an external monitor, it will disappear when I undock the notebbok)

Is it possible to disable it and use something else to manage multimonitor?

Just a question: are you using Qt 5.4 or Qt 5.5?

+https://bugs.kde.org/show_bug.cgi?id=351826 and https://bugs.kde.org/show_bug.cgi?id=353029

You can disable KScreen in system settings, category workspace, module "startup and shutdown". There is an option at background services. The old school configuration per xrandr (https://wiki.archlinux.org/index.php/Xrandr) should work but I wouldn't expect all features of KScreen.

Personally I live with all the bugs (changed my physical environment to deal with) and wait for an update. Dev told me he is working on the tool.

PS: plasmashell -v = Plasma 5.4.2, qtdiag = Qt 5.5.0

My version of qt is 5.5.

I hope they'll fix this soon because it makes working with Plasma5 a hell. Glad to hear that the dev is working on this, because some of this bugs are there since 2 or 3 versions of Plasma but I understand that in the transition phase there's a lot to work on. I guess I'll have to live with these bugs for a while as well.

Might be interesting to you: http://blog.martin-graesslin.com/blog/2 ... -plasma-5/

This is the cause of all the problem with KScreen apparently.

https://www.phoronix.com/scan.php?page= ... iver-crash

Solution: Wait for Qt 5.6 and hope it solves the problems.

> This is the cause of all the problem with KScreen apparently.
Hardly.

Let's say some of them.

Months later. With KDE Framework 5.26.0, opensuse 42.2: still experiencing much of that, even recently spammed the Okular bugtracker https://bugs.kde.org/show_bug.cgi?id=364676 while the app is rather innocent. The same issue happens for Kexi that I develop at the very first startup. Someone would say "it's not our fault" but relying on graphics card/driver vendors (Radeon here) has been known unreliable business for years --I'd wonder how hard it is to allow the user to specify displays once in a profile? Apps like arandr are so simple while doing this. Here I and other users close to me are not changing displays often (not unusual use case) so not unusual question is "why does kdisplay uses the display detection so often?". Disabling it and using xrandr at startup fixes the display switching off but in turn breaks menus in Qt5 (they appear on second display always). This means user that switched to e.g. xfce to from Plasma still has if she uses Qt5 apps. Xfce at least does not unconditionally probe for display changes by default. Breakage is on many levels starting with Qt5 maybe, bug reports start at least in 2014 for X11, and even for Mac.

Summing up, I think it's to early to support automatic display detection in the current state of the hardware...

For others googling for solutions: current workaround apart of replacing hardware is: not using the secondary HDMI screen. Disabling the laptop screen and keeping the HDMI is not a solution because KScreen will probe for changes in a few minutes. When menu item gets displayed, HDMI will be turned off again and only the laptop screen will be available. Worse, Plasma "understands" this change as initiated by the user and it will move all panels to the screen without any consent. In this case don't try to fix position of the panels because after restart they would be back on the HDMI screen with (usually) different geometry.

Solution based on switching away from Plasma: set HDMI as primary, right hand, then disabling the Laptop screen. Example script (works just for me):

xrandr --newmode "1280x1024_60.00" 108.88 1280 1360 1496 1712 1024 1025 1028 1060 -HSync +Vsync
xrandr --addmode HDMI1 "1280x1024_60.00"
xrandr --output HDMI1 --primary --mode "1280x1024_60.00" --pos 1280x0 --rotate normal \
--output LVDS1 --mode 1366x768 --pos 0x0 --rotate normal
xrandr --output LVDS1 --off

PS: Be warned that the new KScreen has no "timeout" functionality when you click "Apply", known for the users for years. So if you make mistake and disable "important" or the only working display there's no way back...