Rated 4 out of 5 stars

The only missing item I see is the Grouped By Sort bars. View -> Sort By -> Grouped By Sort.

This review is for a previous version of the add-on (1.6). 

Thank you for a report.

Because the appearance of original LeopardMail was lost when I included the function by all means, I took off a function.
Please expect it in new Thunderbird 3.
Thank you.