Rated 5 out of 5 stars

The add-on I've been looking for.

It works even with the new Thunderbird 5.0 (you have to edit install.rdf file).

As already stated by JimbosSnackShack Thundebird should have this as default

This review is for a previous version of the add-on (0.4a).  This user has a previous review of this add-on.