Rated 1 out of 5 stars

Works fine in conjunction with Thunderbird's native setting to minimize to tray and a Windows startup folder shortcut set to open Thunderbird minimized.

Only one star because this extension lacks a critical feature -- a right click on the tray icon to pop up a menu with an exit option in order to easily and quickly shut down the program.

This review is for a previous version of the add-on (2.0.1.2).