Mozilla has released Firefox 140.0 to the stable channel, and while this update won’t knock your socks off, it brings some welcome quality-of-life improvements that make the browser a bit more pleasant to use.
Perhaps the most noticeable change is the new vertical tabs enhancement. Users can now resize the pinned tabs section by dragging the divider. It’s a small tweak, but it gives users more control over how they manage space when running many tabs. It feels especially useful for folks juggling pinned tabs like productivity tools or pinned webmail.
Another improvement is tab unloading. You can now right-click any tab and choose to unload it from memory. If you’re the kind of person who leaves dozens of tabs open, this feature can help Firefox chew up less RAM and reduce CPU usage, which could be helpful on older machines or during intense multitasking.
Firefox also now lets users hide the extensions button on the toolbar. While some may prefer quick access, others will appreciate a cleaner interface. The extensions panel is still accessible from the Firefox menu, so nothing’s lost.
Mozilla has made it easier to add custom search engines too. You can right-click in a search field on a supported site and choose “Add Search Engine,” or go into the browser’s settings to enter one manually. Power users who prefer niche engines like Searx or internal site searches will find this change useful.
The browser’s built-in translation system has gotten smarter. Instead of translating an entire page at once, Firefox now prioritizes what’s currently visible on screen. The rest only gets translated when you scroll to it. This approach boosts responsiveness and cuts down on wasted resources.
For international users, the update enables address autofill for Italy, Poland, and Austria. And those running Firefox in Arabic now get a built-in spellchecker with an Arabic dictionary, finally catching up to other major language builds.
In a quieter but notable change, Mozilla has removed the Pocket button from the toolbar and also eliminated Pocket’s New Tab integration. This was expected, as the company previously announced it would be shutting down the Pocket service. It’s the end of an era, though it’s been clear for some time that Mozilla was winding it down.
For web developers, Firefox 140 improves the Inspector tool by adding better search capabilities, including support for pseudo-selector states and DOM element sorting. Under the hood, support has been added for several web platform APIs, including aria-keyshortcuts, CookieStore, the Custom Highlight API, and pointerrawupdate, which enables smoother high-precision input tracking.
One particularly interesting change is that Firefox will now support service workers even in private browsing mode. This means more websites can function fully even when privacy-minded users are in incognito sessions. Mozilla says the supporting data is encrypted.
Also worth noting is a security-focused tweak. Firefox will now escape angle brackets (< and >) when serializing HTML attributes. This can help mitigate mXSS attacks that rely on tricky rendering behavior in certain browsers.
As for known issues, some users running certain dark themes may notice poor contrast in the sidebar. Mozilla recommends switching to the built-in dark or system theme until a fix arrives.
Firefox 140 is available now for Linux, Windows, and macOS. If you haven’t received the update yet, you can check manually from the About Firefox menu.
