Rated 5 out of 5 stars
As mentioned by others, this addon does not work with Thunderbird 38 due to an encoding issue. I've looked at the code, and presented the trivial change needed to restore read/write capability of template files. See http://mesquilla.com/2015/07/15/fixing-quicktext-addon-for-thunderbird/
I've contacted the author asking that this change be done, or someone else released to do the change.
R Kent James
Chair, Thunderbird Council