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!

I have Firefox (always updated to the latest version) and I have noticed a memory leak that EATS up RAM. I have 1 tab open, playing a set spotify playlist. within 24 hours of rebooting the machine, Firefox has swallowed 7gb of my Memory as shown in Activity Monitor/Memory Pressure. I've been having this issue for some time, updates to MACos make no difference either. NO other program does this. I've tested the same playlist in other browsers, Chrome, Safari, uses 1gb, brave/opera uses less than 500mb and they've been open for over a week. This memory leak is a bug in Firefox. I've seen it before (other software, mainly on Windows) but never like this on a Mac......How do I escalate this?

Firefox freezes when I try to sign into YouTube via Google. Becomes totally unresponsive and I have to close browser. It's the only site this happens on. I have cleared the cache and cookies, unchecked "Hardware Acceleration" and other recommendations from other posts. Please talk to me like I'm your Baby Boomer dad.

Upgraded my Mac to Apple OS TAHOE 26.0.1 and upgraded to Firefox 144.0.2 (aarch 64). Upon opening Firefox, the application hogs my computer's 8 GB memory, taking 6.3-7.9 gigs (!!!) with only one tab opened! When I try to browse and use it, it often freezes and for the first time in using MACs for 40 years I got a warning for excessive memory usage and prompt to force quit other apps. Firefox in this version is practically unusable (unless I get 16 gigs of memory!) I think guys that this version uses an excessive amount of resources, needs serious "diet" and compacting. Please fix our favorite browser in a trimmer new version. Or after 30 years nearly I (and many others with * gig machines) will have to switch default browser, not my favorite solution for sure

Having an issue that happeened after updating to Sequoia 15.7.2, when launching Firefox, it opens a new tab, but nothing loads.

Profiles don't load, I'm unable to search anything, unable to even pull up settings.

Have tried reinstalling, clearing NVRAM, deleting profiles in finder.

Hello,

In the DevToolbox, the “Copy all as HAR” and “Create file...” functions are not working. It seems that in both cases, only empty space is placed in the clipboard and in the file (this has been happening since the last update).

Thank you in advance.

My internet browsing gradually gets slower over time. By the end of a day or a couple of days, it is unusable. The problem isn't bandwidth. A speed test shows that throughput is absolutely normal. It's the browser response to navigation. ie clicking a link, typing a URL into address bar, etc. and having to wait minutes for the page to start loading.

If I quit the browser and re-open, everything goes back to normal.

Any ideas what might be the problem?

A couple days ago, some weird issues have started:

• All my bookmarks are gone
• Any of the buttons in the UI that open a smaller UI do not work (such as the 3 bar menu)
• Similarly, right clicking to open a menu (such as "Save Image") also does not work
• Any dropdown menus in websites seem to also not work. For example, in this very support page, I could not select an option in the "Which topic best describes your question?".

I can't restart and troubleshoot Firefox since I can't access the 3 bar menu.

On Windows 11 laptops, I am currently using an Acer Nitro w/ 12th gen Intel i5 16GB RAM, I use my touch pad for scrolling on sites with infinite scrolling. Occasionally this function breaks, when it does it breaks for every tab in the browser window including the setting, I haven't found a singular or specific cause yet. I have troubleshooted it in the community, the prevailing logic being that themes or extensions are causing some incompatibility, so I have reset everything to defaults and made sure I have no extensions loaded, and the problem persists. I can temporarily fix the issue by going into my settings and turning hardware acceleration on and off again. I am writing this to hopefully point out this bug as clearly as possible in hopes that your programmers can fix it in a future update, as repeatedly turning a setting on and off to "fix" it might not be the best solution in the long term.

This problem is persistent and problematic.

Why I am receiving regular message from web page "https://fno.5paisa.com/open-interest/oi-dashboard?name=HINDALCO&exch=N&exchtype=D" that this page is slowing firefox, stop it ?

For the past few months, I have had a problem with my computer - it seems to try to write to a hard disk (sounds like whirring ) and the keyboard freezes up for a few minutes, when whirring in the computer stops. I have taken the computer to Geek Squad two times and they said they found it, but it still happens.

I have just tried Google Chrome and Microsoft Edge and I haven't noticed it. Is this a problem with Firefox or just coincidence?

Mozilla Firefox freezes for 5 to 6 seconds when downloading / saving files or changing the default "Save to" location.

Other programs (i.e. MS Word, MS Excel, Chrome) don't suffer from the same issue.

• I have mapped drives from my NAS on the same network.
• "Automatic Destinations" folder has been cleared
• Looking at the performance stats in Task Manager, CPU and memory usage values are normal.
• Antivirus / firewall software disabled to no affect

Here is the profiler.firefox.com report: https://www.idrive.com/idrive/sh/sh?k=a2a6j1j3o3

Tor browser 14.5.8 (based on Mozilla Firefox 128.14.0esr) LibreWolf 143.0.3-1 Each uses 100% of a CPU thread on Linux Debian 13 (Trixie) with KDE, while internet is not accessible for hours. I have tried to open new empty tab and close single website tab in Tor browser, but that did not decrease the load. Firefox 140.3.1esr also uses around 100% when i count up all its CPU threads load.

Can anyone reproduce this? Maybe the browser needs to run for some time so the issue is reproducible. If you have idea what to try (i will not use different Firefox version), let me know exact steps.

Hello,

we are currently experiencing high memory usage issues with Firefox on our terminal servers.

Problem description: All employees work within a terminal server environment. When using web applications such as Vimcar (https://fleet.vimcar.com) in Firefox, we observe a very high RAM consumption. A single Firefox tab can consume 2 GB of RAM or more after being open for several hours. As a result, the terminal server becomes slow or unresponsive, and other users on the same server are affected. Since the terminal server allocates resources on demand, a hanging process continues to request memory until it eventually terminates itself, which severely impacts overall system performance.

Questions: 1. Are there settings or configuration options to reduce Firefox’s memory usage in terminal server environments? 2. Are there recommended best practices for running Firefox with memory-intensive web applications on terminal servers? 3. Is it possible to set memory limits per tab or per user session to improve stability?

Thank you very much for your assistance.