Firefox 139.0.4 quietly fixes the weirdest bugs — from triple-click fails to blank desktop images

Ever triple-clicked text in Firefox and had nothing happen? Or tried to set a desktop background only to end up with a weird blank filename? If so, the latest Firefox 139 update might be exactly what you needed.

Mozilla is rolling out version 139.0.4 of the Firefox browser, a minor patch that fixes some very specific (and slightly annoying) bugs. It doesn’t come with new features, but it’ll make your browser feel a lot less janky.

Here’s what just got better with Firefox 139.0.4 update:

• Switching between apps or browser panels no longer freezes Firefox on some systems.
• Drop-down menus in the preferences page now behave when using the in-page search.
• Triple-clicking to select text? That works again — even in tricky spots.
• Setting an image as your desktop wallpaper on Windows now uses the right filename (no more blank .BMP files!).

Alongside those fixes, the Firefox 139.0.4 update also patches two high-impact security vulnerabilities. One involved memory corruption when working with canvas surfaces (CVE-2025-49709), and another was an integer overflow deep in the JavaScript engine (CVE-2025-49710).

Also read: Firefox’s Surprising Android Menu Redesign: A First Look at the Upcoming Changes

You can grab the update the usual way: head to Menu > Help > About Firefox, or download it from Mozilla’s site, or the Microsoft Store. Speaking of Firefox, Mozilla recently announced that it is removing some of the services, like Orbit and Deepfake Detector. You can also check the system requirements for Firefox 139.0.4 here.