Icons-Only Task Manager Broken (WAYLAND)

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1

When I use X11 it works fine, when I use wayland it doesn’t work

I have completely reset all my settings, but I can’t find a solution.
I don’t know exactly what I can do to solve the problem.

This problem didn’t exist until a while ago.
It works fine on my old system with the same configuration.
So I’m not sure if the problem is KDE based or nixos based.
They said it might be kde related ( github nixos issue)

Is there such a problem?

Operating System: NixOS 24.11
KDE Plasma Version: 6.2.5
KDE Frameworks Version: 6.8.0
Qt Version: 6.8.1
Kernel Version: 6.12.10

2

hi, i see you are new, welcome … unfortunately you will not be able to post any links or attachments just yet, so you will need to describe the problem you are having in some more detail.

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3

resim
resim1496×1091 162 KB

when any application is open, I can’t follow it because the down side is broken.

If I open any application, it does not appear below.
No icon is created.I can’t see what is active
I don’t have this problem when using x11.

4

Hi - just to check, do you have a custom Global Theme installed? Are you able to check if the issue still occurs if you switch to one of the stock Breeze Global Themes and restart?

5

Hello

I tried all that, but it didn’t help.
I deleted everything, including hidden folders in my user directory.
Despite this, this problem persists in my wayland session.
Actually there seems to be a few other problems but I can’t be sure.
I’m a beginner so I don’t know what to check or how to check.
Can you tell me if there is something you suspect?

6

Hmm…I’m not personally familiar with NixOS, but some folks using it have reported strange Task Manager issues going away by switching away from the unstable channel (475896 – Wayland: Task Manager does not track open windows) or by other steps to re-align where Plasma is expecting files to be with how Nix manages them (Plasma 6.1.3: Pinned kde application icons go blank after GC(NixOS)). Are either of those applicable for you?

Just to check, does the same issue occur with the Icons-and-Text Task Manager? Does Alt-Tab still work correctly?

7

I found the cause of the problem.

Here the controls for monitor brightness were working properly.
I don’t know why, but that’s what was messing up the system (ddcutil)

github. com/NixOS/nixpkgs/blob/nixos-unstable/pkgs/kde/plasma/powerdevil/default.nix
github. com/NixOS/nixpkgs/blob/nixos-24.11/pkgs/kde/plasma/powerdevil/default.nix

I think I won’t be using this anymore.
Thank you.

8

If you have funky hardware that doesn’t like it (my GPU and monitors for example) You can disable powerdevil using ddcutil, like so:

echo '[Service]
Environment="POWERDEVIL_NO_DDCUTIL=1"
'|sudo tee /etc/systemd/user/plasma-powerdevil.service.d/no_ddcutil.conf

(That’s a single, 3-line copy-paste)

Then

systemctl --user daemon-reload; systemctl --user restart plasma-powerdevil.service

Should result in

> systemctl --user status plasma-powerdevil.service
● plasma-powerdevil.service - Powerdevil
     Loaded: loaded (/usr/lib/systemd/user/plasma-powerdevil.service; static)
    Drop-In: /etc/systemd/user/plasma-powerdevil.service.d
             └─no_ddcutil.conf
     Active: active (running) since Sun 2025-01-26 08:55:55 AEDT; 7s ago
...

It’s nice because then you can keep ddcutil around and use it, but it won’t be used by KDE.

If you decide you don’t want this any more,

sudo rm /etc/systemd/user/plasma-powerdevil.service.d/no_ddcutil.conf

systemctl --user daemon-reload; systemctl --user restart plasma-powerdevil.service

But… I can’t imagine how sending hardware commands to your monitor (that’s what ddcutil does), could change the content of your plasma panel. It can make your whole screen go black, or it can make it flicker, or make the brightness go crazy, turn off the USB hub in the monitor, that kind of thing, but it can’t change the content of the applications. It’s almost certainly not this.