Rated 4 out of 5 stars

Just loaded this add-on and I'm very happy with it for incoming messages.

But it has an omission, which wasn't clear until I installed it:

I wish it worked for outgoing messages (i.e the "write" or compose screens). They have an unreasonably small display font, but if I increase the font size to be readable as I compose, it displays way too large if the recipient is using Thunderbird, and maybe some other email clients as well.

This review is for a previous version of the add-on (1.0.8). 

Thanks for bringing that to my attention. I'm also working on adding functionality to the task window, too.