FolderPulse

A Thunderbird extension that automatically refreshes virtual folder views (saved search folders and virtual tag folders) when their contents change.

Problem

Thunderbird's virtual folders don't update their message list view in real time. The folder pane may show updated unread counts, but the actual message list remains stale until you navigate away and back. This is a known bug that has been open for 15+ years.

How it works

FolderPulse monitors displayed folders for changes using two mechanisms:

• Event-driven: Listens to onFolderInfoChanged and messages.onUpdated to detect new messages and tag changes immediately.
• Polling fallback: Checks folder message counts every 5 seconds via the alarms API, which survives Thunderbird's MV3 background page suspension.

When a change is detected, it forces a view refresh by briefly switching to the account inbox and back (the "two-step switch" method).

Requirements

• Thunderbird 128+ (ESR)

Installation

1. Download folderpulse.xpi from the latest release, or build it yourself:

   zip -r folderpulse.xpi manifest.json background.js

2. In Thunderbird, go to Add-ons Manager → Install Add-on From File and select the .xpi file.

License

MIT