1978868 - The browser does not synchronize the theme with the GTK theme of the cinnamon environment

Status: RESOLVED DUPLICATE of bug 1978639

(Firefox :: Shell Integration, defect)

Description

[Robin Lugo Boero]

Attachment: Screenshots of the error

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:141.0) Gecko/20100101 Firefox/141.0

Steps to reproduce:

Steps to reproduce the error:

1. Set the environment theme to GTK Light.
2. Start the browser. The browser and window themes match (GTK Light).
3. Change the environment window theme to dark. The browser detects the changes and automatically switches to dark mode.
4. Restart the browser. The browser starts in light mode, replacing the environment window theme, which is set to dark.

Actual results:

The browser starts by default in a light GTK theme, regardless of the environment theme. For example, when starting the browser with the environment set to GTK Light and then manually changing the environment theme to GTK Dark, the browser detects the change and switches to dark mode. The problem arises when restarting the browser. After restarting the browser, the theme does not synchronize with the environment theme (which is set to GTK Dark), leaving it in light mode by default. The environment in which this error occurs is Cinnamon.

Expected results:

The browser should sync the theme with the GTK theme of the application environment upon startup. In this case, if the applications are found to use the dark theme, the browser should launch in dark mode.

Comment 1

[Robin Lugo Boero]

Attachment: Captura de pantalla de 2025-07-23 09-48-41.png

Comment 2

[Robin Lugo Boero]

Attachment: Captura de pantalla de 2025-07-23 09-49-00.png

Comment 3

[Robin Lugo Boero]

Attachment: Captura de pantalla de 2025-07-23 09-49-24.png

Comment 4

[Robin Lugo Boero]

Attachment: Captura de pantalla de 2025-07-23 10-12-42.png

Comment 5

[Alice0775 White]

Seems duplication of Bug 1978698, Bug 1978639.

Comment 6

[Robin Lugo Boero]

(In reply to Alice0775 White from comment #5)

Seems duplication of Bug 1978698, Bug 1978639.

Exactly. It's the same problem.

Comment 8

[Duncan McIntosh [:dmcintosh]]

Since this is the same as Bug 1978639, I'll mark this a duplicate of that one.

Given you're using Cinnamon, I assume you're using Linux Mint, in which case this seems to be waiting on a fix from the Linux Mint side; some people are posting workarounds in https://github.com/linuxmint/cinnamon/issues/12994, and it looks like a fix is in the works. If you aren't on Mint, the workarounds presumably would still work, and hopefully backports will fix the xdg-desktop-portal issue in due time.

(Quick bonus question, if you want—do GTK4+libadwaita applications (most recent GNOME ones, flat appearance) have the same problem? It looks like we should work the same as they do.)