Rated 4 out of 5 stars

by radioguyuhf on Jan. 8, 2018 ·

Found link to Happy One and re-installed Theme and Font Size Changer. So far it is working.

Thank you Steven

This review is for a previous version of the add-on (62.0). 

Rated 1 out of 5 stars

by radioguyuhf on Jan. 7, 2018 ·

No longer works on my Window 7 computer.
None of the solutions I have found will work.
I would ask Thunderbird developers to incorporate Theme and Font changes inside Thunderbird itself without using an ADD-ON or extension. If this doesn't happen I will be forced to use a different email program. It will be a sad day as I have used Thunderbird for many years. Thunderbird may be near the end of its life-cycle and if so, then so be it.
My 5 star rating is now a 1 star.

If anyone does have a real solution that really will work, please advise.

This review is for a previous version of the add-on (62.0).