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itsoulos

Member

Registered: 2020-12-19

Posts: 94

.gtkrc-q4os

Hello all,
can I alter this file in my home directory to change the appearance  of gtk apps such as Firefox and Thunderbird?

Regards

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,107

Website

Re: .gtkrc-q4os

This file would affect Gtk2 applications, what is not the case of Firefox and Thunderbird.

itsoulos

Member

Registered: 2020-12-19

Posts: 94

Re: .gtkrc-q4os

This file would affect Gtk2 applications, what is not the case of Firefox and Thunderbird.

Is there any file or setting to change the appearance of Firefox and Thunderbird to match the kde settings?

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,107

Website

Re: .gtkrc-q4os

Firefox and Thunderbird are GTK apps, not Qt ones. Here are some tips by AI, as we have checked:

1. Use KDE’s GTK integration
Open System Settings → Appearance → Application Style → Configure GNOME/GTK Application Style
Make sure:
GTK theme is set to Breeze (or Breeze Dark)
Icons match your KDE icon theme
Font matches your Plasma font

2. Install the Breeze GTK theme (if missing)
$ sudo apt install breeze-gtk-theme
Once installed, re-select it in the GTK settings above.

3. Make sure xdg-desktop-portal-kde is active
This helps Firefox/Thunderbird respect KDE dialogs, file pickers, and theming.
Install packages:
xdg-desktop-portal
xdg-desktop-portal-kde
Then log out and back in.
You can check it’s working by opening a file dialog in Firefox — it should look like a KDE dialog, not GNOME’s.

4. Firefox-specific tweaks (very useful)
Open Firefox and go to:
about:config
Check or set these:
Force GTK theme usage
widget.gtk.theme.override = Breeze
(or Breeze-Dark)
Prefer system dialogs
widget.use-xdg-desktop-portal = true
Restart Firefox after changing these.

5. Thunderbird (same engine, fewer knobs)
Thunderbird uses the same GTK stack, so:
It follows the GTK theme automatically
No equivalent about:config tweaks are usually needed
Just restart it after GTK changes
If it still looks off, make sure it’s not using a custom Thunderbird theme.

6. Colors & dark mode gotchas
If dark mode isn’t syncing:
Plasma: Appearance → Colors
GTK: must also be Breeze Dark
Firefox: set theme to System theme – auto
Firefox won’t follow KDE accent colors perfectly, but it’ll get close somehow.

itsoulos

Member

Registered: 2020-12-19

Posts: 94

Re: .gtkrc-q4os

Thank you very much
I had to set the widget.use-xdg-desktop-portal  to 1  in order to use the native dialogs of kde

Best regards

bin

Member

From: U.K.

Registered: 2016-01-28

Posts: 1,560

Re: .gtkrc-q4os

In Firefox Customise Toolbar and bottom left click Title Bar - that way it will use the same window controls as Plasma.

itsoulos

Member

Registered: 2020-12-19

Posts: 94

Re: .gtkrc-q4os

In Firefox Customise Toolbar and bottom left click Title Bar - that way it will use the same window controls as Plasma.

Where are these settings?

bin

Member

From: U.K.

Registered: 2016-01-28

Posts: 1,560

Re: .gtkrc-q4os

Right click on the tab area - say, to the right of a new tab button. Then go down to Customise Toolbar

Last edited by bin (2026-02-08 12:39)

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itsoulos

Member

Registered: 2020-12-19

Posts: 94

Re: .gtkrc-q4os

Right click on the tab area - say, to the right of a new tab button. Then go down to Customise Toolbar

I have already done this and I have installed the plasma addon

itsoulos

Member

Registered: 2020-12-19

Posts: 94

Re: .gtkrc-q4os

Right click on the tab area - say, to the right of a new tab button. Then go down to Customise Toolbar

I have already done this and I have installed the plasma addon

I think that is solved now.