Rated 5 out of 5 stars

One of the BEST addons.
However, after upgrading to Thundrbird 45 it does not read/load the existing templates any more, neither creates/saves new ones.

Many, many, many thanks to gregor111 for his fix on April 22, 2016.
https://addons.mozilla.org/en-GB/thunderbird/user/gregor111/

This review is for a previous version of the add-on (0.9.11.6).