Facebook Messenger Flash — Netherium

Facebook Messenger Taskbar Flash restores Windows taskbar alerts for Facebook Messenger in Firefox. When a new message arrives while Messenger is in the background, its taskbar button flashes until you focus the window.

• Targets the existing Messenger web-app window without opening another client.
• Detects unread changes using the page title and visible accessibility indicators instead of fragile generated class names.
• Repeats the attention request until Messenger receives focus.
• Includes a three-second manual test so you can verify taskbar flashing immediately.
• Runs entirely on your computer with no analytics, telemetry, advertising, or data transmission.

Designed for Firefox 143 or later on Windows. Messenger must remain open as a Firefox web app or regular Firefox window.

This is an unofficial independent project and is not affiliated with, endorsed by, or sponsored by Meta Platforms, Inc.