Bug 464207 - GTK4 programs are not themed to Breeze, when it is selected
Summary: GTK4 programs are not themed to Breeze, when it is selected
Status: RESOLVED DOWNSTREAM
Alias: None
Product: Breeze
Classification: Plasma
Component: gtk theme (other bugs)
Version First Reported In: 5.26.4
Platform: Manjaro Linux
: NOR normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2023-01-12 17:18 UTC by Mors Mortium
Modified: 2025-10-03 18:27 UTC (History)
9 users (show)

See Also:
Latest Commit:
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Sentry Crash Report:


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Description Mors Mortium 2023-01-12 17:18:02 UTC
SUMMARY
***
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***


STEPS TO REPRODUCE
1. Install any GTK4 program (gtk4-demos)
2. Choose Breeze as GTK theme
3. Start GTK4 program

OBSERVED RESULT
GTK4 program uses adwaita theme

EXPECTED RESULT
GTK4 program uses Breeze theme

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 5.26.4
KDE Frameworks Version: 5.101.0
Qt Version: 5.15.7

ADDITIONAL INFORMATION
A workaround for this is setting the environment variable ``` GTK_THEME=Breeze ```
Comment 1 Nate Graham 2023-01-12 19:49:50 UTC
Are these apps using libadwaita for their theming, or not?
Comment 2 Mors Mortium 2023-01-12 20:32:40 UTC
The example app (gtk4-demos) does not need libadwaita, and it is reproducible without libadwaita installed. Other GTK4 (not libadawaita) programs, with which this can be reproduced are gtkcord4, vte4.
Comment 3 Nate Graham 2023-01-12 21:26:44 UTC
OK, thanks.
Comment 4 Yannick 2025-10-01 08:56:43 UTC
I can now reproduce this issue on Arch Linux with GTK 4.20.2.

No issue with GTK2 or GTK3 apps, and it didn't happen with GTK 4.18.x

Setting GTK_THEME=Breeze is indeed a valid workaround.
Comment 5 Victor 2025-10-01 12:27:54 UTC
I can reproduce this issue too

Arch Linux / GTK4 4.20.1-1

I had to use the workaround (GTK_THEME=Breeze) manually in GTK4 apps like LACT
Comment 6 Boctor 2025-10-03 01:25:27 UTC
This happens with all GTK4 applications on Wayland for me, too. I am also on Arch.

Only forcing them to run as X clients with GDK_BACKEND makes them respect settings. They do not respect anything configured in $HOME/.config/gtk-4.0/ when running as native Wayland clients. This includes icons, fonts and font sizes, too, which are defaulting back to Cantarell 11 on everything. It seems like the gsettings prefs are also now being ignored by GTK4. I've tried with GTK 4.20.1 and 4.20.2, with no apparent differences.
Comment 7 Mors Mortium 2025-10-03 16:16:26 UTC
https://gitlab.archlinux.org/archlinux/packaging/packages/gtk4/-/issues/14 Possibly related for the Arch users. I am not sure if my issue can be reproduced still, since this happened on Plasma 5 and Manjaro and I use Plasma 6 and Artix now
Comment 8 Yannick 2025-10-03 18:23:00 UTC
(In reply to Mors Mortium from comment #7)
> https://gitlab.archlinux.org/archlinux/packaging/packages/gtk4/-/issues/14
> Possibly related for the Arch users. I am not sure if my issue can be
> reproduced still, since this happened on Plasma 5 and Manjaro and I use
> Plasma 6 and Artix now

I confirm that this was related.
The issue has just been fixed in gtk4 4.20.2-2. Non-libadwaita gtk4 applications now use the Breeze theme (or any other configured theme) as they should.
Comment 9 Mors Mortium 2025-10-03 18:27:40 UTC
Alright, since the recent issue was fixed and the old issue can't be reproduced even by me, the reporter, I'll close this.