Rated 4 out of 5 stars

Installing is actually really easy just not well explained.

1. Download the add-on to your desktop.

2. Open the Add-on's window from Tools on the Menu bar

3. Simply drag-and-drop the download into the Add-on's window

4. When instructed restart Thunderbird.

AFZ

This review is for a previous version of the add-on (1.19).