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As above themes not working on latest version of firefox difficulty reading menu & tabs bar as light blue needs to be dark coloured

Also have difficulty reading your website because of white background will not work on dark mode retinopathy burn

As of 12/9/25, Firefox seems to now prevent Theme add-ons from working if there is a contrast setting configured in Windows configuration. (Version 146.0) Previously, this allowed a very aesthetically pleasing view. I would greatly enjoy having that option again. Thank you.

Turns out you cant use your own stuff until it is approved, Sorry for this question I am absolutely new to firefox workshop. Case closed (Please delete it because I couldn't find how to do that)

Hello!

SECERITY: LOW, COSMETIC DESCR.: I love how many yhere are beautiful themes for ff. I Like to install any the I think is beautiful and keep enjoing all of them by switching them to see it on FF itself. Now - not aftyer every change of active theme, but after a few/scrooling the order of the Themes on list is re-sorted. It is a little trouble for me as I like to chnge/watch them afew times a day (like person who like to watch theirs clothes, how their look in that clothes, so they keep changing them and see how they look in the mirror). So Id like the list of themes to be fixed, so I can go throuh the whole list and make sure I didn't missed any of my installed themes. OK, I hope I manage to explain it. I'm 40+ yo soft dev. so you can ask me technicall questions. And also: a setting among about:config to change this list behavior whould be absolutely enough solution for me.

Best regards, Michał Dąbrowski

As per my title, where can I find a themes toolbar background image and change it? I have tried looking for manifest.json and header.png files for the theme but I can't find it.

Or is there a way I can override it using CSS somewhere?

Windows 11

Cheers

GW

i am unable to see my installed themes and therefore can not use them. the only thing that i can see is "extensions" and "plugins". i looked online for a few hours and have found no solutions that work.

Hi, I rebooted Firefox today because a website was frozen, and when it came back, it was asking for a troubleshoot or just continue, and I don't know exactly what that meant, but when I clicked on refresh, everything was changed, including the theme. And then when I tried to restore the theme back to the original it said, add-ons are disabled by safety, and I don't know what that means, and it's not explaining how to undo it. And now everything looks different and I'm not happy with it, and it's not really letting me add any other themes, and if I add them, they don't seem to fully load, the page still looks all white

Dear Mozilla Support Team,

I am writing to report an issue I have consistently encountered while using the Firefox browser. Whenever I log into my Mozilla account, the custom theme I have selected for Firefox is reset to the default theme. This necessitates manually re-selecting my preferred theme each time I log in.

This issue is a minor inconvenience, but it disrupts my user experience. I would appreciate it if you could investigate this behavior. I am using the latest version of Firefox on Windows 11 Pro.

Thank you for your time and attention to this matter. I look forward to a resolution.

Sincerely,

Clóvis Lauriano [edited email from public]

Best regards,

At the beginning of 2025, I created a private theme and installed it locally (Windows 10), consisting of a manifest.json and a GIF file. It worked perfectly. Now, on Windows 11, I'm trying to use the theme again, but when I upload the file (.zip or .xpi — via about:addons -> Install Add-on From File), I always get the message that the file is corrupted. However, if I test it temporarily under about:debugging, it works immediately without any issues.

I would really appreciate a solution! <3

Does anyone else have the issue where the interface just looks bad? It's like I'm using an old version of Microsoft office on a Windows 3.1 machine. I see in the settings I can change the font sizes for composing emails but how about the system interface? Others say "just download a theme" but could someone recommend one? This current font makes me want to delete this software and look for alternatives. I only checked out this software because Microsoft sucks. And I'm about ready to leave this one also.

Thunderbird version 142.0 (64-bit) Windows 11 build 26100.4652 Intel Core i5-9400F 32GB ram

Greetings!

I downloaded a theme that I really like for Thunderbird, but I would like to ask for your help. I would like to change part of the frame to a different color (similar to the one on the left), but I don't know how to do it. I am attaching a photo where I have circled the part I would like to change with red lines.

Thanks for your answers!

Igor

My question: is there a way to force a light TB theme and use white tab background text color?

I installed a theme add-on which I like except the associated dark theme. I want to use the theme image with a light TB theme but it appears the tab background text color determines the theme color (light or dark). This image has some darker colors and a light/white tab text looks the best, but this color seems to force a dark theme for the rest of TB (White text ->dark theme). If I change the manifest file to use a different tab background text color I can change the overall theme to light or dark. Using a darker or black tab background text color the theme changes to a light theme. Light tab background text color changes to a dark theme and darker tab background text colors forces a light them. I'm guessing there is a threshold 1/2 way between black and white text that will force the theme one way or another.

The articles I have read on this json file don't provide any examples and this is as far as I have been able to get. I'm new to both TB and modifying this json file. Any help would be appreciated

I’m at my wits’ end with this. Firefox keeps forcing a system-synced theme at launch, and it flat-out refuses to respect the settings I’ve configured — both in about:config and via a custom user.js file.

Here’s what I’ve tried:

• Set layout.css.prefers-color-scheme.content-override to 0 in about:config → it reverts back to 2 after every restart.

• Created a user.js with user_pref("layout.css.prefers-color-scheme.content-override", 0); → completely ignored.

• Disabled all sync options, including themes.

• Verified that no active studies are interfering.

• Double-checked that I’m not syncing across devices.

• Tried applying a specific theme and setting it manually — still overridden at launch.

No matter what I do, Firefox insists on syncing the theme to the system’s dark/light setting. I want my browser theme independent from the OS — period.

Is there a deeper setting I’m missing? A hidden override? Some service that’s reapplying the system setting post-launch? This feels like Firefox is actively fighting me — and it's infuriating.

Would appreciate any insight or workaround. I just want full manual control over my theme. Why is that so hard?

I am trying to change my Theme and every time I enable a new theme, it changes for a minute but then it reverts back to the old theme that I can't even find anywhere in Thunderbird or on my computer. How do I get the new theme to "stick"?