Rated 4 out of 5 stars

Slows down the deletion of mails & RSS feeds dremendously (when pressing the DEL-key repeatedly - lets say 20 times - in order to delete 20 rss feeds from the thread pane).
After deactivating the Add-On, everything works normal/fast again.

This review is for a previous version of the add-on (3.2). 

Problem resolved

This problem is fixed in Version 3.3 which works with Thunderbird 3.1.