Hello Wayne Merry

I think your missing the point when you say we should email the publisher of the add-on.

Mozilla and Thunderbird muck up add-ons every second week with their updates. Certain add-ons should really be standard features of TB and this is one of them cos with 75,000 add-on users, it's clear that the default font size was decided by a cretin, albeit one with 10/10 vision :)

That said, I thank you and all the moderators for their hard work. I'm not ungrateful but I say what I think when it's necessary.

Regards

SafeTex

The add-on contains a term which makes it expire. I don't pretend to understand the reason.

A regular contributor to the newslist has prepared a modified version:

http://www.rossde.com/ThemeFontSizeChangerNoexpire/index.html

You will need to "install from file" to make use of the downloaded xpi file.

https://support.mozilla.org/en-US/kb/installing-addon-thunderbird