Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
Google and Zimbra contact sync for Thunderbird. (TB 24 and above NOT supported)
Note from Mozilla: This add-on has been discontinued. Try MinimizeToTray Revived instead.
Minimize applications to the system tray.