I-Firefox Community Forum

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 can not get rid of the pink background in the address bar, search box or background space of yahoo mail. I can not find the revert to default theme as previous post from several years ago suggested as a solution.

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

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.

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

I recently updated to Firefox 135.0 on MacBook Pro, Catalina, OS 10.15.7 In the past, with multiple Firefox windows open & multiple tabs open in each, when restarting, "reopen pages on startup" selected, system loaded & ready to go, I'd find all windows, tabs & history available upon launching Firefox. Since update to 135.0, shut down & restart, launch Firefox and I find a single blank new window, no multiple windows, no tabs, no history. I've tried to find [Settings] to make everything come back - no joy, to no avail. Suggestions? Help? Thanks, JS

I am unable to remove add on themes. The remove button is not provided. Only manage which enables the theme. I do not want these themes and want them removed now. mac ios

I set a theme with https://addons.mozilla.org/en-US/fire.../firefox-color/(Firefox Color), I tried changing the theme in settings to light or dark but neither work. I'm wondering if there are other ways to do so in Firefox that I could try. I'm on zen browser which is why it may not have worked.

I have literally over 200 tabs open at a time and recover them every time I reboot Firefox, but they are very disorganized. Is there a good way to organize them, for example, group related tabs together?

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)

you are repeating old mistakes. You have become worse than Microsoft. Firefox is not remembering open tabs again. I have supported your Firefox until now but enough is enough.

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]