Bug 448877

Summary:	kde-gtk-config doesn't work as expected when switching preferred color scheme.
Product:	[Plasma] Breeze	Reporter:	Emilio Cobos Álvarez (:emilio) <emilio>
Component:	gtk theme	Assignee:	Janet Blackquill <uhhadd>
Status:	CONFIRMED ---
Severity:	normal	CC:	4wy78uwh, azrdev, bharadwaj.raju777, hujq, kde, nate, peter, plasma-bugs-null, postix
Priority:	NOR
Version First Reported In:	master
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:
Attachments:	firefox-nightly-log.txt A Demonstration Of Switching `.colors` Operating As Expected On 6.4.4

Description Emilio Cobos Álvarez (:emilio) 2022-01-21 13:03:40 UTC

SUMMARY

See the discussion in https://bugzilla.mozilla.org/show_bug.cgi?id=1734934#c17 and following. STR are just having Firefox or other GTK apps with the breeze theme and switching color-scheme.

I think there are various issues in the kde-gtk-module:

 * I _think_ `ConfigEditor::addImportStatementsToGtkCssUserFile` is unnecessary, since the colorreload module will also load the colors.css file. Worse, it prevents colorreload from actually doing its job, since the `gtk.css` loaded statements won't be removed. This causes Firefox and other GTK apps need a full restart to see theme changes.

 * `GtkConfig::setDarkThemePreference` is not harmful, but seems redundant with the newer portal-based settings.

 * The default Breeze theme doesn't react to the `gtk-application-prefer-dark-theme` setting, since it will use the colors from `colors.css` unconditionally.

All these issues cause GTK apps seem less polished than they should, even though there's nothing those apps can realistically do to avoid it.

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 36
KDE Plasma Version: 5.23.90
KDE Frameworks Version: 5.90.0
Qt Version: 5.15.2
Kernel Version: 5.17.0-0.rc0.20220112gitdaadb3bd0e8d.63.fc36.x86_64 (64-bit)
Graphics Platform: Wayland

Comment 1 Bharadwaj Raju 2022-01-21 15:58:52 UTC

Created attachment 145717 [details]
firefox-nightly-log.txt

Log of what Firefox Nightly outputs with MOZ_LOG=LookAndFeel:5 as I change the colorscheme back and forth. Might be useful. Done on nonexistent profile.

Comment 2 Nate Graham 2022-05-17 19:01:07 UTC

Please feel free to submit merge requests to fix these issues, Emilio!

Comment 3 Emilio Cobos Álvarez (:emilio) 2022-05-20 11:21:21 UTC

Yeah, happy to, it's on my list of things to get to. I realized it's a bit trickier because on Wayland GTK doesn't load the colorreload module, so it's not so straight-forward unfortunately.

Improving the breeze theme to react to the dark theme setting should be doable and would be a massive improvement tho, I just need to find the time to figure out the best solution for that.

Comment 4 Nate Graham 2022-05-21 17:28:30 UTC

Great, I look forward to it!

Comment 5 Roke Julian Lockhart Beedell 2025-08-30 10:08:53 UTC

Created attachment 184577 [details]
A Demonstration Of Switching `.colors` Operating As Expected On 6.4.4

(In reply to Emilio Cobos Álvarez (:emilio) from comment #0)

> Firefox and other GTK apps need a full restart to see theme changes.

I don't *see* this anymore, if of use: 

> ~~~
> Operating System: Fedora Linux 42
> KDE Plasma Version: 6.4.4
> KDE Frameworks Version: 6.17.0
> Qt Version: 6.9.1
> Kernel Version: 6.15.10-200.fc42.x86_64 (64-bit)
> Graphics Platform: Wayland
> ~~~

I definitely used to, so something has changed.

The attached screencast depicts Firefox reacting, but GTK4 + LibAdwaita `flatseal-2.3.1-1.fc42.noarch` also reacts at the same speed that any Qt application does.