Rated 5 out of 5 stars

my current version: 0.4.20.
I have been using this for a while. In the past I have had some problems losing groups. Just now however, working in gmail, I renamed some groups, created some, deleted some and also deleted a bunch of 'suggested contacts'. I then re-opened Thunderbird and it worked perfectly.

This review is for a previous version of the add-on (0.5.10).