Firefox Community Forum

For a while now firefox has been unable to enter fullscreen when pressing F11. Instead all it does is move the "Scroll forwards", "Open a new tab", and "List all tabs" button over slightly (The buttons on the top right, next to the minimize and close buttons).

I don't know what's going on with firefox.

Firefox Version 142.0.1 (64-bit)

The font size in "Manage Bookmarks" is way too large, both in the sections list menu on the left and the list of bookmarks. I checked my userChrome.css file as well as the layout.css.devPixelsPerPx entry in about:config and there's nothing there to explain why only the "Manage Bookmarks" text is so large.

It's possible I changed a setting somewhere that's causing this. But I'm stumped re: what setting might be controlling the font size in only that UI. All other Firefox text sizes are good.

Thanks to anyone who knows where I should be looking

Firefox 134.0.1 (64-bit) Windows 10

These are technically two separate issues, but both pertain to functionality of the mouse and keyboard. Whenever I right click to bring up the menu, the options (despite being functional) do not appear in the menu proper. Instead there are just empty buttons. In addition, certain hotkeys aren't working at all. Ctrl+C and Ctrl+V to copy paste are doing fine, but Ctrl-T and Ctrl-W to open and close tabs respectively do nothing. Neither of these issues were happening yesterday.

When I swipe to the left, Firefox navigates Back & when I swipe to the right, Firefox navigates Forwards. It is VERY ANNOYING!!!! It's really easy to do this accidentally while scrolling around a large web page. When you go back, it deletes all data that was filled out on the web form causing DOUBLE the work. How do I turn it off please? Win 10, FF 142.0.1 64-Bit

The keyboard shortcut to take screenshots [Ctrl + Shift + S] used to work a few weeks ago but it has stopped working for quite a while now. Doesn't work on any site, I can only create screenshots by right clicking and pressing the button manually.

I uncheckd the checked box labled "check spelling as you type" to disable it and it's still showing spellcheck. It's gettingin the way of me typing and being able to spell on my own. It's extremely annoying that I can turn off a featire and the progra will just ingore that I've turened it off. Why is this an actualy problem? why doesn't this button just work? I want it OFF... Please.

Hello,

I wanted to customize my Firefox new tab with a local HTML file, such as "/path/to/my/index.html". It was possible to use this workaround: https://github.com/Jangsoodlor/Firefox-New-Tab-Config/tree/main https://github.com/Jangsoodlor/Firefox-New-Tab-Config/tree/main

Which implied a configuration file (sometimes named "autoconfig.cfg", "firefox.cfg", "local-settings.cfg" depending on the guide since the name is arbitrary) with javascript code. In the new Firefox 136, this code fails to execute due to a new API being used.

If you want to customize your new tab, follow the previous guide, but on the configuration file write this code instead:

// My new tab
try {
  const ff = {};
  ChromeUtils.defineESModuleGetters(ff, {AboutNewTab: "resource:///modules/AboutNewTab.sys.mjs"});
  ff.AboutNewTab.newTabURL = 'file:///path/to/my/index.html';
} catch (e) {ChromeUtils.reportError(e);}

Note that the file must start with a comment

Adapting the "/path/to/my/index.html" to your needs.

Thanks to @mkaply (github) on this thread https://github.com/mozilla/policy-templates/discussions/1190 for the new API method.

I post this here in case someone has the same issue, because is quite recent and hard to find on the internet.

New installation of Debian 13, Firefox setup with sync on successful. However, I wanted to add hone button and a few other mods to the toolbar but when I started customize the toolbar from menu pic the customization page would not work, it appeared and seemed OK but when I dragged and dropped anything it would not work. I could pickup items but they would not place in toolbar and just snapped back to the pallet. I tried several different ways to enter the customization area but it was always non-functional.

I opened Firefox today to find that nothing would show up, at first I tried clicking on the icon on the taskbar, but it just made the icon bounce with the window briefly popping into view. That's when I realized that Firefox was completely offscreen and unusable.

For context, last night, I had 3 windows open, two were regular sessions, the last one was a private session I had open on a temporary second monitor that I unplugged afterward. My dad lended it to me, so I'd rather not ask him again unless I absolutely have to. I closed them in order making sure to close the default window last thinking that Firefox would open there next time I launch it, but comes tomorrow and when I launch Firefox it opens off-screen and I can't interact with the window at all.

There also seems to be no way to bring it back directly to my screen on this garbage OS everyone calls "windows 11" according to their help forum: https://learn.microsoft.com/en-us/answers/questions/4139775/app-runs-off-screen-in-windows-11?page=2#answers

So, I'm commenting here via brave browser, first to report a bug because I don't think Firefox should remember the last position of a private window of all things, but also because I don't know where else to go to ask that question since windows 11 itself cannot seem to have an option to solve this problem either. I know the position is stored in the profile folder, so what should I edit in there to get Firefox back where it should be? No, I will not delete/reset it it has a ton of search engines and settings that Firefox won't sync.

On Firefox 128.14.0esr (build 20250811113756), Linux/X11, the setting browser.tabs.hoverPreview.enabled does change back to "true" every few days, or perhaps browser restarts.

How can I turn off tab previews reliably?

I've found out that you can create custom prompts for the AI sidebar with the configuration `browser.ml.chat.prompts.*`. Usually, this is done with the selection text. However, I'd like to pass the URL instead. I could use `%url%`, but that does not include parameters after `?` and hence does not work for Youtube.

Is there any variable that I can use to pass the full URL including parameters of the URL?

There is a 'feature' in Firefox that I think is called "click and hold context menu". Basically if you left click on something and hold the click for a second or two a menu appears that offers an AI generated list of suggestions related to the thing you were clicking on. How do I disable this? In searching I have found suggestions to open about:config and set the value for ui.click_hold_context_menus to false, which I have done a few weeks ago now and it has no affect. I also tried changing the related value of ui.click_hold_context_menus.delay to an insanely long time, but that also had no effect.

I would appreciate some guidance on how to turn this off. This is problematic enough that I may have to switch to another browser if this can't be disabled. Thanks! Attached is a random example of one of these context menu's that appears when clicking and holding on a link.

Thanks to the help received here and in the Reddit group I've been able to transfer almost all of my old colour and layout tweaks to a new intallation of Firefox (v133) on a new PC (running Windows 10). There's one thing that I haven't succeeded with though: I'd like to change the colour of the text in a tab when that tab becomes the active one.

This is the coding I'm using to change the tab's background colour when it's selected:

1. TabsToolbar .tab-background[selected]{

background: white !important; }

This works perfectly. But when I tried adding the line

color: black !important;

It had no effect. I'd be grateful for any thoughts. Many thanks.

`StartupWMClass=firefox-aurora` in `/usr/share/applications/firefox-devedition.desktop`, with actually `firefox-dev` for opened windows.

Version: Ubuntu 25.04, GNOME 48, firefox-devedition 143.0b2.