I'm always on the lookout for new/handy userscripts. Just wondering what ones that you use?

I used to be able to close tabs using a the standard little "x" icon on each tab. Now its gone.

That means I have to click on the tab to close it.

That means I have to wait until the page is entirely reloaded.

On a cellular internet connection - or any connection that isn't always highspeed - that's a real pain in the ass.

WTF, Firefox?

nice to be back and see the fox runs good now left it for a long time after the slow downs bugs and it just up and crash at random times but dang man its nice now runs good and fast so no more chrome as the main browser 🦊

Release Notes

Download 64Bit

Firefox 159.0 key highlights (Beta — features and fixes may change before the final release)

• Smart Window can monitor web pages for price drops, restocks, and other changes using /watch, with configurable check intervals, desktop notifications, and controls to manage watches.
• macOS sharing now uses the native share picker, with page previews, recent contacts, AirDrop, Messages, and support for sharing multiple tabs.
• Saved passwords are now accessible directly from the sidebar by default.
• Fixed excessive memory usage on Linux with AMD graphics when viewing maps and place results on sites such as ChatGPT.
• Fixed rapid memory growth when minimized web apps, including Zoom, were left open.
• Firefox for Android has improved tab reloading, particularly on Xiaomi and Redmi devices.
• Fixed video playback failures on Firefox for Android affecting sites such as The New York Times.
• Fixed videos displaying incorrectly on Windows when NVIDIA RTX Video HDR is enabled.
• Fixed websites such as Slack failing to load when HTTP/3 requests were rejected, restoring fallback to HTTP/2.
• Fixed bookmarks failing to import from Google Chrome profiles signed in to a Google account.
• Open tabs can now be searched using Ctrl+Shift+A on Windows/Linux or Cmd+Shift+A on macOS. Keyboard shortcuts can be customized in about:keyboard.
• macOS apps that use the default browser for sign-in, including ChatGPT, now open authentication pages in Firefox when it is the default browser.
• The AI chatbot's Summarize page option now shares the page URL with the chatbot provider instead of sending the page's text content.
• Added support for CSS and Web Animations API scroll-driven animations, including animation-timeline, scroll-timeline, view-timeline, and animation-range.
• Added support for scoped custom element registries, allowing custom elements with the same tag name to coexist on a page using separate registries.

Source

I am on Windows 11, PC with 80GB Ram (truth).

Firefox has the laggiest video across not only Youtube, but streaming sites. It's sometimes a 5 second delay, often 12 and I've waited 24 seconds on some sites. This does not happen on Edge, Chrome----I switched to firefox for good reasons but I'm at a point that work is slowed down If video is so inconsistent.

I did have it working once ---lots of turn this on, turn this off, about config stuff but firefox--in one of it's routine updates blew ALL My configs out of the water, didn't honor my save settings during the update and here I am back at zero.

What is the top list of things to do that will mostly likely guarantee a sound video experience

On no other browser I've used have I had to toggle hardware acceleration off? on? turn my ad protection off, clear my cache weekly? These routinized hoops to make it work suck.

I want set and forget----

again clearing a browser cache has not been an issue with any other browers to assure performance, not for me in 8-10 years.

https://www.firefox.com/firefox/153.6.0/releasenotes/ & https://www.firefox.com/firefox/115.44.0/releasenotes/

I recall it was off for a long time before, but this button came back recently with Nova. Is there an about:config flag to hide it? Or is this something that I need CSS to deal with?

The new PDF viewer is fine and all, but there is one bug with it that needs to be addressed and the sooner the better. As I wrote in the title, if I open PDF in the new viewer and try to download it, it always uses the name "document.pdf". Right click on the PDF and choosing Save page as has the same result. The only workaround I found so far is to go back to the page that linked said PDF, right click the link and choose Save as. That is the only way to save PDF under its proper name. And that's very annoying. This really needs to be fixed.

Was playing ark when I noticed a popup window appear for a couple seconds. I checked task manager but didn’t see anything suspicious and windows defender didn’t find anything, after I was done gaming I tried opening Firefox and got a message saying it’s corrupted and unreadable. I’ve been using Firefox for a couple years and never encountered this, I’m just wondering if anyone else had this issue before. I’ve Already reinstalled

EDIT: turns out Nocturne (FF work) IS on Linux, so no need to tinker with Firefox anymore :)

EDIT 2: mb, it’s NOT on linux :p

Whenever I'm on Reddit on the desktop, typing into the comments field or the body of this posts is very difficult because the UI and cursor are about 0.25-0.5 seconds behind my actual keystrokes. Oddly enough, I can type into the title of this post with no lag, but the body is very laggy. Switching to markdown mode does seem to fix the lag, but I like to be able to format text, generally.

This seems to have started within the last week or so. I'm running FireFox 159 on Windows 26H2. Installed extensions are UBlock Origin, iCloud Passwords, and iCloud Bookmarks.

Clicking the shield icon used to bring Site information window and View Certificate option. Now clicking it does nothing and just show the cert is verified, no option to view certificate.
(Version 159.0)

I originally wrote this for a friend. Here is what I wrote with minor modifications. I hope everyone finds it useful because I saw similar requests on the Firefox support forum.

Problem

A user opens the "Default Apps" section of Windows Settings and clicks on "Set defaults by apps", only to find two Firefox entries in the list. Why?

Solution

The Firefox installer may register itself twice with the system, once under HKEY_LOCAL_MACHINE and a second time under HKEY_CURRENT_USER:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\RegisteredApplications]
"Firefox-308046B0AF4A39CB"="Software\\Clients\\StartMenuInternet\\Firefox-308046B0AF4A39CB\\Capabilities"

[HKEY_LOCAL_MACHINE\SOFTWARE\RegisteredApplications]
"Firefox-308046B0AF4A39CB"="Software\\Clients\\StartMenuInternet\\Firefox-308046B0AF4A39CB\\Capabilities"

Delete the right key (NOT both). If Firefox is installed for the entire machine, delete the HKEY_CURRENT_USER entry once for every user. If Firefox is installed for one user only, delete the HKEY_LOCAL_MACHINE one (needs admin privileges).

Further reading

Firefox may have duplicate registration data under:

• HKEY_CURRENT_USER\SOFTWARE\Clients\StartMenuInternet\ (e.g., as Firefox-308046B0AF4A39CB)
• HKEY_LOCAL_MACHINE\SOFTWARE\Clients\StartMenuInternet\ (e.g., as Firefox-308046B0AF4A39CB)

Again, delete the right one, although these don't contribute to the problem mentioned above.

The new vertical tabs design in Nova looks horrible with the container tabs. Thanks to Claude AI (!!), I made this code for the userChrome.css file that give a design inspired by the container tabs feature in Brave Browser.

How to :

• In about:config, set toolkit.legacyUserProfileCustomizations.stylesheets to true.
• In about:support, on the “Profile Folder” line, click “Open Folder.”
• Create a “chrome” folder in that directory, then create a “userChrome.css” file inside the “chrome” folder.
• Restart Firefox after each change to the file.

UPDATE 2026-10-27 : Code updated for better pinned container tabs.

/* CONTAINERS DESIGN FOR FIREFOX NOVA, BRAVE STYLE
*
* Colored block on the left with the container icon, tinted background and border,
* highlighted active tab. Vertical tabs.
*
* Rules with [usercontextid] only apply to container tabs.
*/


/* ===== Container tabs only ===== */

/* Background and border tinted with the container color */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid] .tab-background {
  position: relative !important;
  background-color: color-mix(in srgb, var(--identity-tab-color) 10%, transparent) !important;
  outline: 1px solid color-mix(in srgb, var(--identity-tab-color) 35%, transparent) !important;
  outline-offset: -1px !important;
}

/* Hover: slightly stronger tint */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid]:not([selected]):hover .tab-background {
  background-color: color-mix(in srgb, var(--identity-tab-color) 16%, transparent) !important;
}

/* Active tab: stronger tint and solid border */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid][selected] .tab-background {
  background-color: color-mix(in srgb, var(--identity-tab-color) 18%, transparent) !important;
  outline-color: var(--identity-tab-color) !important;
}

/* Color block on the left of the tab */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid]:not([pinned]) .tab-context-line {
  position: absolute !important;
  inset-block: 1px !important;          /* 1px gap top & bottom */
  inset-inline-start: 1px !important;   /* 1px gap on the left */
  inset-inline-end: auto !important;
  width: 26px !important;               /* size of the block */
  height: auto !important;
  margin: 0 !important;
  border-block: 0 !important;
  border-radius: calc(var(--tab-border-radius) - 1px) 0 0 calc(var(--tab-border-radius) - 1px) !important; /* rounded left, straight right */
  background: color-mix(in srgb, var(--identity-tab-color) 30%, transparent) !important;
  mask-image: none !important;
  opacity: 1 !important;
}

/* Solid block on the active tab */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid][selected]:not([pinned]) .tab-context-line {
  background: var(--identity-tab-color) !important;
}

/* Container icon inside the block (in the container color) */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid]:not([pinned]) .tab-context-line::before {
  content: "" !important;
  position: absolute !important;
  inset: 0 !important;
  background-color: var(--identity-tab-color) !important;
  mask: var(--identity-icon) center / 14px no-repeat !important;
}

/* White icon on the active tab */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid][selected]:not([pinned]) .tab-context-line::before {
  background-color: white !important;
}

/* Shift the favicon and title past the block */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid]:not([pinned]) .tab-content {
  padding-inline-start: 36px !important;
}

/* Space between the block and the favicon */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid]:not([pinned]) .tab-icon-stack {
  margin-inline-start: 6px !important;
}

/* Pinned container tabs: no block or line, only the background and border */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[usercontextid][pinned] .tab-context-line {
  display: none !important;
}


/* ===== All tabs ===== */

/* Keep the tab group line continuous and off the tab */
#tabbrowser-tabs[orient="vertical"] .tab-group-line {
  inset-block: -6px !important;         /* stretch over the gaps between tabs */
  inset-inline-start: -8px !important;  /* move it left, away from the tab */
}

/* No fade on tab titles
#tabbrowser-tabs[orient="vertical"] .tab-label-container {
  mask-image: none !important;
}
*/

/* Inactive tabs: hide the X until hovered */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab:not([selected]):not([pinned]) .tab-close-button {
  display: flex !important;
  visibility: hidden !important;
}

#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab:not([selected]):not([pinned]):hover .tab-close-button {
  visibility: visible !important;
  opacity: 1 !important;
}

/* Pinned tabs: never show the X */
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab[pinned] .tab-close-button {
  display: none !important;
}


/* ===== OPTIONAL: subtle border on inactive regular tabs =====
*  This section is DISABLED. To enable it: add an asterisk and a slash
*  at the end of the START line below, then a slash and an asterisk
*  at the beginning of the END line.
*/

/* START
#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab:not([usercontextid]):not([selected]) .tab-background {
  outline: 1px solid color-mix(in srgb, currentColor 18%, transparent) !important;
  outline-offset: -1px !important;
}

#tabbrowser-tabs[orient="vertical"] .tabbrowser-tab:not([usercontextid]):not([selected]):hover .tab-background {
  outline-color: color-mix(in srgb, currentColor 30%, transparent) !important;
}
END */

So it seems the 157 issue of not remembering upload locations was fixed in 159 just now as discussed in https://bugzilla.mozilla.org/show_bug.cgi?id=2077656 but it looks like it's still not been resolved for the about:debugging page when loading temporary add-ons?

It still does the incorrect behavior that started in 157 of looking at the most recent upload location instead of where it was uploaded from last. Was wondering if anyone else has tested this behavior after updating.

If one keeps the tabs in a session and closes and reopen the browser, firefox will not contact and download those sites until the user opens the specific tab.

But if the sites are saved in bookmarks or history, and the user opens multiple, the sites will load. This will often cause a 429 error because sites don't wanna be bombarded by requests, rightly so.

So, is there a way to put bookmarked sites into the tab bar but without loading the sites?

My keyboard has several media keys, however, only the "pause" key actually works. The skip/fast forward ones aren't recognized. Is it possible to manually set which keys are used?