Firefox Community Forum

This started happening a few days ago.

I tried to drag a tab out of the main window to put it in its own window on my other monitor, but the tab just became unselectable, and if i scrolled in the tab bar, the tab icon and text would remain locked in place in the display while the other tabs moved behind it.

The main Firefox window also lost the minimize, restore, and close buttons. The only way to make the tabs work was to close Firefox and relaunch it.

I noticed this happened only after any app in the OS went full screen, be it a steam game, or another Firefox window, or a VLC window, or anything else that I did that made an app full screen in any of my monitors.

I am using Ubuntu 24.04 with KDE Plasma 5.27.12. Kernel is 6.14.0-29. Display server is Wayland.

Initially I thought this could be a problem with the snap version of Firefox, so now I've installed the deb package, but the problem remains. Firefox is the only app which presents a problem of any kind when any window goes full screen.

Here's a video showing what the problem looks like, in case my description was not clear. The ghostly tab in this video is the chess.com home page and you can see it as the third tab from the top right of the video, and it remains in that position as i scroll the other tabs, completely unselectable with the mouse.

https://www.youtube.com/watch?v=-mAfPS3_qkg

Any idea of what could be causing this issue to appear?

Thank you!

After tinkering with about:config (shouldn't have...) the background of every page that does not specify a body background color turns the color of my theme background color.

Using the firefox color pipette says its white, but it clearly isn't.

The theme i have is dark, making any page that expects the background to be white unreadable (without DevTools -> Body -> background-color: white)

I haven't been able to find the config that fixes it.

I have a local file I wish to view in firefox without starting a HTTP server (it's only docs for a crate I'm building) however Firefox is unable to open the file despite the file existing and having correct permissions. The file was in a separate mount (disk) to where Ffox is installed so I copied to to /tmp/ to remove that as a variable but still no joy..

➜ ~ file /tmp/index.html /tmp/index.html: HTML document, Unicode text, UTF-8 text, with very long lines (3556) ➜ ~ ls -la /tmp/index.html -rwxr-xr-x 1 ben ben 4208 Dec 30 14:04 /tmp/index.html

Am I missing some new setting which allows local file browsing using the good old 'file:///' protocol?

Thanks, Ben

OS Info: PRETTY_NAME="Ubuntu 24.04.3 LTS" NAME="Ubuntu" VERSION="24.04.3 LTS (Noble Numbat)" VERSION_CODENAME=noble

F/Fox version: 146.0.1 (64-bit)

https://www.datilcam.com/weather/index.htm

The website you are blocking is on my domain and is my website. Why are you blocking it? Stop blocking it!

After upgrading my 128 esr to 140 esr, some sites stopped opening. In regular versions, it has not opened for a long time. There are many such sites, for example, qwen3.app or temp-mail.io. It thinks for a long time and finally a message that the time has expired. Chromium is ok.

I read firefox is dropping linux 32. Are there any alternatives?

I only use the internet to watch youtube videos.

I don't feel like having to buy a new laptop for this.

https://support.mozilla.org/en-US/kb/firefox-has-ended-support-32-bit-linux#firefox:linux:fx144

Hello,

i was trying to check my apparmor stuff because of the warning on Linux. Now i tried duck.ai to instruct me , but created more damage than anything else. It said to set firefox in enforcement mode, now it wont start (well im using Firefox right now in complain mode)

How do I fix this problem that everything runs normally and safe?

Please help me! madmorph666@madmorph666-E14301:~$ sudo aa-complain /usr/bin/firefox /usr/bin/firefox wird in den Complain-Modus versetzt. madmorph666@madmorph666-E14301:~$ firefox ATTENTION: default value of option mesa_glthread overridden by environment. [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed [Parent 72019, Main Thread] WARNING: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_widget_get_clipboard: assertion 'gtk_widget_has_screen (widget)' failed [Parent 72019, Main Thread] WARNING: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(firefox:72019): Gtk-CRITICAL **: 03:12:17.894: gtk_clipboard_request_contents: assertion 'clipboard != NULL' failed ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. [Child 72430, Main Thread] WARNING: Unable to open /var/lib/flatpak/exports/share/dconf/profile/user: Keine Berechtigung: 'glib warning', file /builds/worker/checkouts/gecko/toolkit/xre/nsSigHandlers.cpp:201

(/usr/lib/firefox/firefox-bin:72430): dconf-WARNING **: 03:12:53.181: Unable to open /var/lib/flatpak/exports/share/dconf/profile/user: Keine Berechtigung ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment. ATTENTION: default value of option mesa_glthread overridden by environment.

When I have multiple tabs open, around the 6th tab, the entire computer freezes. I have to press the physical button to shut down and restart. This behavior started with the last Firefox update. It doesn't happen when I use Brave browser. What changed to cause this?

I'm running Mozilla Firefox for Linux Mint mint 100 - 1.0 version 141.0.3 (64 bit) on Linux Mint 22.1 Cinnamon. These are the latest versions of Mint and of Firefox for Mint.

Firefox used to save unknown files according to the save files setting. i.e. ask where to save files. Now if opens unknown files as text in a new tab.

How can the correct behavior be restored?

Alternately, can the Linux snap be fixed to allow saving of new file types? {The procedure shown in https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file is not present in the firefox 141 snap.

I have an Investors.com account and a feature they offer is a stock sector data table that shows recent performance and other information. When I try to open these tables they close immediately, but if I use my tablet with a different browser they will remain open. I believe this is a simple setting that I need to adjust, but I don't know enough to figure it out.

I rebooted my laptop with both firefox windows I had open and possibly a private window too, then rebooted again without touching firefox, and now I can only restore one of the two windows. I checked my recently closed windows in history and there was nothing there at all. Is there anything I can do at all to restore that other window or is it just gone for good now?

I am now receiving this notice for more and more commonly accessed websites. I get the message if I have https only selected or not selected. Currently receiving for Lowes, Home Depot, American Airlines and more. I can go to a Firefox 135.0.1 browser on a separate desktop accessing the internet through the same router and do not have issues. I suspect I have been upgraded by Mozilla into a less functional browser version for whatever reason that Mozilla does this.

Sample Messages:

American Airlines Access Denied You don't have permission to access "http://www.aa.com/" on this server.

Reference #18.ea382f17.1754673395.2abc2b02

https://errors.edgesuite.net/18.ea382f17.1754673395.2abc2b02

Lowes Access Denied You don't have permission to access "http://www.lowes.com/search?" on this server.

Reference #18.89f8cd17.1754677280.265017bc

https://errors.edgesuite.net/18.89f8cd17.1754677280.265017bc

I recently got a new machine and loaded it with Linux Mint 21.3 - Cinnamon, FF 142.0 and Bitwarden Version: 2025.8.2 along with the usual cadre of extensions that I use on every other machine I have.

When I first start Firefox, Bitwarden autofill suggestions does not work, autofill from the "Fill" button in Bitwarden does not work and returns an error. The only thing that works is to individually and manually copy the username, paste it, then copy the password and paste it.

If I log out of Reddit and then try to log back in, the autofill suggestions works and the "Fill" button also works.

This is only on Firefox and only on the fresh start of the app. This does not occur on Chrome and I have not tried (and don't want to try) it on Windows.

Hi, I'm using Firefox 142 on Ubuntu 24.04. It's a fresh install. I cannot sign in icloud.com with Firefox even though it works with other browsers like Brave. I deleted all cookies and site data and disabled extensions (KeePassXC). It doesn't help. I tried in new private window. No success. I copy my password from a password manager, so, no, I haven't mistyped it.

Here's what I do:

1. Open Firefox and go to icloud.com
2. Click on the "Sign In" button
3. Enter my Apple-ID and click on the arrow on the right end of the "Email or Phone Number" field

At this point Brave behaves differently than Firefox. See below for how Brave behaves.

Firefox: -> A "Password" field appears (no buttons "Continue with Password" and "Sign in with Passkey")

1. Enter my password and click on the arrow on the right end of the "Password" field

-> Error message "Failed to verify your identity. Try again" appears. See icloud.png

Brave: -> Two buttons "Continue with Password" and "Sign in with Passkey" appear. See icloud-with-brave.png

1. Click on button "Continue with Password"

-> A "Password" field appears.

1. Enter my password and click on the arrow on the right end of the "Password" field

-> 2FA code is sent to my iPhone -> "Two-Factor Authentication" form opens... etc. complete sign in successfully

Please help!

Unfortunately I cannot attach the HAR file from the login sequence because the password is included. However, I attached some screenshots from the Web Developer Tools. It seems to me that the login flow with Firefox is broken. I can't tell who's to blame, Apple of Firefox. The error message with Firefox is always the same, no matter whether I enter the correct password or rubbish. In Brave, however, there is a more precise error message when I enter a bad password. See icloud-with-brave-wrong-password.png

Hello! See the screenshot please: so, I downloaded à pay-bill, with Firefox (under ubuntu), in private navigation, and I get the file with a padlock-symbol at the end. What means that? What means that for me (on my computer), what means that for à friend, when I sent him the pdt-file (can he open it?). Nota: I understood that I can choose between "delete downloads when closing the privat window" or not. And I choosed not to delete them (but there appears this padlock-symbol). Thanks for your help! Michael from France

Crash submitted, ID = 320cc808-4505-4cba-6e0f-9f2c2955d007 Still happens in troubleshoot mode. Still happens with extensions disabled (Ublock origin, Proton Pass) Started happening since Dec. 5, 2025 System is current with all Debian?Ubuntu updates installed (daily refreshes) Linux Kernel 6.8 on Lenovo Yoga i7 (ca. 2022) with Intel i5 & Intel graphics

Hi Mozilla I hav got a problem with Firefox on Kubuntu 24.04.3. Everytime the computer is restarted Firefox crashes the first time it's started. That's not a big problem, starting Firefox again don't take long. But the problems is exceeding. If i start Firefox by clicking a link in a mail in Thunderbird. And Firefox has not yet been started, It crashes, but now it's also invaliding the Task bar on the screen where Firefox was started. Invaliding means that I cannot start apps from that screens taskbar, and the clock has stalled, none of the tools works etc. The only possibility solution I have been able to figure out, is restart (It's like going back to Win 98). Sometimes I am able to start a app from that invalid taskbar. But it's not the one app that i clicked on. Even though I can trigger it via Thunderbird, the invaliding of the taskbar will occur after a while. And I have to restart. I am not sure if this is the right place to post. But Firefox is always involved, but maybe Thunderbird or Ubuntu was the right place? Every time Firefox crashes there is send a crash report to Mozilla, but is has been going on for a while, so i guess that nobody is looking at the crash report. If I use Chromium instead of Firefox I don't see the problem.

Since Flathub list the org.mozilla.firefox app as official, i hope this is the correct support channel.

Recently i switched from distro specific package managers to flatpak as my application provider. The firefox flatpak won't play most embedded Video/Media on applications like in-browser fediverse clients, forums, blogs or wikis. Youtube works without any issues, Twitch is fine until there is an adbreak. Then it sometimes stops with the supported format/mime error (screenshot appended), only recoverable by cache-dismissive reload.

I used this Article https://support.mozilla.org/en-US/kb/audio-and-video-firefox and the links it contains to debug without any success. None of these samples play. just shows supported format/mime error https://test-videos.co.uk/bigbuckbunny/mp4-h265 At this test website 1. and 3. example won't play. I provided a screenshot before and after trying to click play on all the examples. https://www.tekeye.uk/html/html5-video-test-page

Contrary to the observed behavior about:support#media claims Software Decoding supported for everything except HEVC.

Chromium Flatpak has no such issues. So i copy the video url and play it with chromium. You can see: dire times.