Floorp Browser 12.20.2 Updates to Firefox 158, Fixes Memory Reclaim and Window Cleanup

For Windows users evaluating alternative Gecko-based browsers alongside Linux and macOS counterparts, Floorp 12.20.2 is a practical maintenance release that cleans up window lifecycle management and synchronizes upstream Mozilla fixes.

Moving to the Firefox 158 Runtime​

At the core of Floorp 12.20.2 is the transition to the Firefox 158 runtime (tracked in pull request #2926), replacing the Firefox 157.0.1 base introduced in the 12.20.0 and 12.20.1 releases earlier in October. According to the official Floorp release notes, this base update brings in upstream bug fixes and security patches from Mozilla's Firefox 158 advisory.

It is worth noting a common point of confusion in third-party software listings: while standard promotional descriptions on Neowin often describe Floorp as running on a four-week Firefox Extended Support Release (ESR) cycle, Floorp 12's actual release manifests track rapid-release Firefox runtime numbers directly—jumping from 157.0 in late September to 157.0.1 on October 6, and now to 158 on October 17. Neither Floorp's release blog nor its GitHub changelog singles out a specific emergency CVE in this build, framing it instead as routine upstream parity combined with targeted browser maintenance.

Section Summary: Floorp 12.20.2 upgrades its engine from Firefox 157.0.1 to Firefox 158, pulling in upstream Mozilla bug and security fixes without introducing breaking changes to user profiles.

Memory Reclaim and Window Resource Cleanup​

If you keep dozens of tabs, sidebars, and Web Panels open across multiple monitors, browser memory management is more than an academic talking point. Floorp 12.20.1, released on October 9, previously tackled rapid memory growth and freezes caused by missing Fluent localization labels in context menus. Version 12.20.2 follows up by addressing two distinct resource management behaviors (#2929):

• Idle Memory Reclaim Persistence: Floorp includes an optional idle memory reclaim feature designed to trim memory usage when the browser is inactive. Prior to 12.20.2, restarting the browser could cause idle memory reclaim to silently stop running, even though the toggle remained enabled in settings. The update restores proper initialization so the reclaim logic continues operating according to configured rules across browser restarts.
• Window and Web Panel Teardown: Closing a browser window or unloading one of Floorp's signature sidebar Web Panels previously left behind active observers and event handlers. The 12.20.2 update explicitly strips out unneeded Web App (PWA) observers, Chrome extension confirmation handlers, and command-palette toggle listeners when their parent window or panel closes.
• Multi-Window Chrome Extension Prompts: When installing a Chrome extension, Floorp customizes the installation confirmation prompt. Previously, state could bleed across multiple open browser windows. The confirmation UI now stays strictly bound to the window where the installation started, and any leftover installation tasks are purged when that window closes.

The project presents these changes as lifecycle and reliability corrections rather than promising a specific megabyte reduction on your Windows Task Manager readout. Still, ensuring that closed windows actually release their observers is essential housekeeping for long-running desktop sessions.

Section Summary: The update fixes a bug that disabled idle memory reclaim after a browser restart and cleans up lingering event handlers when windows or sidebar Web Panels are closed.

Interface, Command Palette, and Settings Fixes​

Beyond resource cleanup, several user-facing interface elements received repairs in 12.20.2. Many of these touch the Command Palette and sidebar controls introduced or expanded in the 12.20.x branch:

• Settings Sliders and Command Palette Controls (#2909): Floorp replaced Chakra UI sliders and wired up Seekbar values properly so that adjustments made to command-palette sliders actually register and persist in the underlying settings values.
• Command Palette Lifecycle: Toggling the Command Palette feature off and back on previously caused display state glitches and accumulated duplicate shutdown handlers; both issues have been resolved.
• Theme and Status Bar Persistence: Closing one browser window while other Floorp windows remained open could strip the active theme and status-bar buttons from the surviving windows. Those visual elements are now preserved across open windows.
• Settings and Welcome Page Links (#2898): External links clicked inside about:hub (Settings) and about:welcome were failing to open. The actor handling for these internal pages has been repaired.
• Contextual Search Suggestions: Generating site-specific contextual search suggestions before the browser's search-engine configuration finished loading could trigger internal errors. Floorp now guards against premature suggestion generation.
• Build-Time JSON Preferences (#2923): A build-system bug that caused certain JSON-valued default preferences to generate improperly across override runs has been patched, alongside new pre-publication QA verification for signed packages (#2886).

Section Summary: Everyday usability improvements in 12.20.2 restore working external links in Settings, keep themes intact when closing secondary windows, and synchronize slider controls with saved preferences.

macOS App Shim Fixes and the Reinstall Caveat​

While Windows users get all the runtime and UI fixes automatically upon updating, cross-platform users running Floorp on macOS have an extra step to keep in mind. Pull requests #2915, #2901, and #2916 update the macOS native App Shim for Firefox 158 compatibility and resolve two irritating input bugs in experimental macOS Web Apps distributed through Floorp Flasco:

• Pressing the Spacebar repeatedly to cycle through Japanese IME conversion candidates no longer overwrites the active composition with blank whitespace.
• Stale input state that blocked standard editing commands like Paste inside editable fields has been fixed.

According to Floorp's release documentation, these fixes only apply to experimental native Web Apps on macOS. Furthermore, updating the core Floorp browser is not enough to repair an already-installed macOS Web App—users must reinstall the affected Web App after updating to Floorp 12.20.2 for the Japanese input fix to take effect. Standard browser tabs and Windows installations are unaffected by this shim limitation.

Section Summary: macOS users utilizing experimental native Web Apps get fixes for Japanese text input and Paste commands, though existing Web Apps must be reinstalled after the browser update to apply the IME fix.

Package Breakdown for Windows and Linux​

Floorp is distributed under the Mozilla Public License 2.0 (MPL-2.0) and provides signed release assets directly through GitHub. If you are downloading or auditing the 12.20.2 packages manually, here is how the official release assets break down across platforms:

For Windows 10 and Windows 11 systems, the 111 MB floorp-windows-x86_64.installer.exe package is the standard offline installer suitable for clean deployments or manual upgrades, while existing installations will typically pull the MAR update automatically through the browser's built-in updater.

If you have been testing Floorp 12 as a daily driver for its vertical tabs, dual sidebars, or workspace isolation, version 12.20.2 is a sensible, low-risk update that makes sure your memory reclaim settings and multi-window layouts behave the way they were supposed to in the first place.

Correction (October 18, 2026): the 12.20.1 build hash was corrected from 576bc4b to 724dc8f (576bc4b is the 12.20.2 release commit, per the Floorp GitHub releases API), and the Firefox 157.0.1 rollout date was corrected from October 8 to October 6, 2026, per Mozilla's Firefox 157.0.1 release notes.