Bug 470429 - Screen shows as "disconnected" after switching monitor. Missing desktop background and panel.
Summary: Screen shows as "disconnected" after switching monitor. Missing desktop backg...
Alias: None
Product: plasmashell
Classification: Plasma
Component: Desktop Containment (show other bugs)
Version: 5.27.4
Platform: Ubuntu Linux
: NOR normal
Target Milestone: 1.0
Assignee: Plasma Bugs List
Keywords: multiscreen
Depends on:
Reported: 2023-05-29 20:34 UTC by leonardopsantos
Modified: 2023-08-14 02:12 UTC (History)
4 users (show)

See Also:
Latest Commit:
Version Fixed In:

Panels and Desktop Management screenshot (184.82 KB, image/png)
2023-05-29 20:34 UTC, leonardopsantos

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Description leonardopsantos 2023-05-29 20:34:14 UTC
Created attachment 159330 [details]
Panels and Desktop Management screenshot


Panel gone from one of my multi-monitor setup.

My setup is not very exotic: 

- Laptop attached screen
- External HP Z27 (through a USB 3 Thunderbolt cable)
- External HP Z27 (through an HDMI cable)

The panel is missing from the HDMI monitor.

Both HP Z27 are also connected to a desktop system running Windows 11. Sometimes, when I switch between inputs in one monitor, (say, KDE -> Win) and then back, KDE kill glitch and (usually) the HDMI HP Z27 will just loose the desktop: no panel, no background image.

If I go to the " Panels and Desktop Management", I see three screen, with the one corresponding to the HDMI monitor showing as "Disconnected" (see attached image). That's is incorrect, it's working fine, I can drag any window to or from it.

System Information:

Operating System: Kubuntu 23.04
KDE Plasma Version: 5.27.4
KDE Frameworks Version: 5.104.0
Qt Version: 5.15.8
Kernel Version: 6.2.0-20-generic (64-bit)
Graphics Platform: X11
Processors: 8 × Intel® Core™ i5-8265U CPU @ 1.60GHz
Memory: 15.3 GiB of RAM
Graphics Processor: Mesa Intel® UHD Graphics 620
Manufacturer: LENOVO
Product Name: 20QD001UUS
System Version: ThinkPad X1 Carbon 7th

plasmashell: 5.27.4
kernel: Linux 6.2.0-20-generic #20-Ubuntu SMP PREEMPT_DYNAMIC Thu Apr  6 07:48:48 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

Maybe bug #427278 ins't fixed?




Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

Comment 1 leonardopsantos 2023-05-29 20:38:12 UTC
Workaround mention in comment 8 of bug #427278 works for me:


My script is:

systemctl --user stop plasma-plasmashell
cp -af $HOME/custom/backup/panels/$SRC/* $HOME/.config/
sleep 5
systemctl --user start plasma-plasmashell
Comment 2 Roy Orbitson 2023-08-14 02:12:34 UTC
I regularly encounter the same issue on a similar setup: two external monitors on a notebook and the built-in monitor disabled. Physically unplugging then reconnecting the "disconnected" display usually gets its connection status reset.. After doing this, I sometimes need to use the Panels and Desktop Management dialogue to move thins back to the correct monitors.

I don't know if it's a separate issue but, like bug 427278, Plasma will also "forget" the config eventually, and at a fresh login will have incorrect monitors enabled/disabled or has the externals as duplicates of each other, though I've never set it that way. The login screen (sddm?) never seems to respect these arrangement settings, and will re-enable the built-in monitor and/or disable one of the externals.

I tried using autorandr, which applies profiles perfectly from manual invocation, but seems to conflict with Plasma's own automatic detection. If anyone knows how to disable Plasma's detection so I can try autorandr properly, please tell me.

I reduce the frustration by backing up this config (after I've made any changes and everything's arranged right):
cp -a ~/.config/plasma-org.kde.plasma{,-BACKUP}.desktop-appletsrc
When things go awry again, I log out of any graphical sessions, open a TTY session, restore it as follows, then log in again:
cp -a ~/.config/plasma-org.kde.plasma{-BACKUP,}.desktop-appletsrc