Rated 1 out of 5 stars

Nice button. That's about it. Nice button.

Doesn't do anything. No zoom with this add-on.

This review is for a previous version of the add-on (0.0.6). 

No Zoom?

Will you please tell me what operating system that you're using and what version of Thunderbird?

This add-on has been available on this site since February 28, 2012 and this is the first time that I've heard that it doesn't work. I use it myself.
It accesses and triggers Thunderbird's default zoom feature and that's about all there is to it.