Diễn đàn hỗ trợ Firefox

I need to call an executable script that I wrote when I click on a link to a file of a certain file type. I used to be able to browse to my script in order to set it as the desired application, but now I can't find any way to persuade Firefox to call my script when, for example, the linked-to file's name ends in '.dng'. Where is the list of such applications, and how do I add my script to it?

Hello, I have been aware of this issue for about a month now. I have, for example, added 3 sites to my "Block" list under "Manage Exceptions" in "Cookies and Site Data". They are not only repeatedly disappearing from the exceptions list without my input (which I suppose is the bigger issue), but even when they are present, the websites still end up storing cookies and site data for the session. These sites are Wikipedia, Bing, and DuckDuckGo.

In addition, I've also added a finance website to the "Allow" list, as the browser is set to delete cookies on quit. This website has also repeatedly disappeared from the exceptions list without my input.

My version of Firefox updates regularly via the Linux Update manager. I am also wondering if the "Forget about this site" option in the History menu generates this (at least to me) unexpected behaviour. I would expect that using the "Forget about this site" option would delete site data, cookies, and history, but not remove it from my Cookies exception list...

I've been trying to set up 2fA on my firefox account, the whole process seems to work, I downloaded the backup codes and entered one to confirm and then got confirmation that 2FA was enabled (see screenshot). However, after reloading the page 2fA is shown as being disabled and indeed if I try to log out then in again I'm not asked for a code. I've tried this a couple of times now and it does the same every time. The auth app I'm using is Aegis.

Does anyone knows why this is happening ? Thanks.

[Edit: I just saw that after each time I tried to set it up, in "recent account activity" I add an error saying "Two-step authentication failed" which doesn't really makes sense...]

https://gist.github.com/ben-j-c/6d15852955d04c9018600d15d4a8a13e

Context: Here is an animation I generate with a program I'm developing. It being an SVG makes it useful to open in a web-browser. In chromium based browsers I have smooth animation, while in firefox I get much worse performance. At larger animations the problem becomes much more apparent. This is the approximately the largest animation that firefox can handle without lagging too much.

Expected: Firefox should have comparable SVG animation performance as chromium.

Hi, Using FireFox to log into Le Chat Mistral doesn’t work on my Ubuntu 22.04 PC. I enter the email to verify the A/C then enter the code number. Next it says ‘You successfully verified your email address’ and pressing 'Continue' I go back to 'Verify your account' page and round we go again??. There is no problem on my Windows 11 laptop so what's the issue with Ubuntu or have I done something silly? Thanks

I'm using Firefox on Ubuntu, and every time the browser crashes and I reopen it, I get the "Start New Session" or "Restore Previous Session" prompt. I’ve tried both options at different times, but in either case, I find myself logged out of Gmail.

This is quite frustrating, especially considering the number of authentication steps required to log back in (e.g., 2FA, verification prompts, etc.).

It seems like session cookies or state information aren’t being properly preserved or restored after a crash. I had high hopes from Firefox in terms of privacy and stability, but this issue is seriously affecting my workflow.

Has anyone else faced this? Is there a way to ensure that sessions (especially login sessions like Gmail) are preserved after a crash?

Any help or suggestions would be appreciated!

Fix for RangeError: invalid language tag and client-side exceptions in Firefox on Linux

Hi everyone, I was experiencing persistent JavaScript errors in Firefox on Linux when loading certain modern websites (e.g., built with React or Next.js). The browser console showed messages like:

   RangeError: invalid language tag: "chrome://global/locale/intl.properties"

   A client-side exception has occurred (see the browser console for more information)
   React error #418 with minified stack traces

This happened even in Safe Mode, with all extensions disabled, cookies/cache cleared, and Enhanced Tracking Protection off. ✅ Root cause and fix:

Turns out the issue was related to missing or broken locale configuration in Firefox. To fix it:

   Open about:config

   Create a new string entry:

       Name: intl.locale.requested

       Value: en-US (or fr, en-GB, etc. — any valid locale)

   Restart Firefox

After adding this key, all affected pages started working correctly. The invalid "chrome://global/locale/intl.properties" error in intl.accept_languages disappeared as well — it seems that was just a side effect of the missing locale setting. 🔁 Summary:

If you’re seeing RangeError: invalid language tag and React crashes, try adding intl.locale.requested manually. This fixed the issue entirely for me on Linux.

Hope this helps others!

Hi all, I'm using Firefox 140.0.4 (64-bit) on Debian Trixie and I'm getting a weird behavior with the auto-complete functionality of the address bar.

If I type the first character the address gets auto filled (see 20250711_First-character-auto-fill-working.png attachment), then if I type the second character the auto filled result disappears (see 20250711_Second-character-auto-fill-NOT-working.png).

I've tried any search option combination, but results doesn't change. At the moment I'm using for the address bar just "Browsing history" (see 20250711_Address-bar-settings.png).

The correct behavior would be, as in the past, that new characters confirming the address would leave things as they are. Do you have any suggestion on how to restore the original behavior?

Many thanks,

Raoul