Rated 5 out of 5 stars

O.K. if you're still struggling without Copy Sent to Current on Thunderbird 3.1, click on the link on this page "Visit the support site", find and download 0.9.5.3 & you should be O.K.

This review is for a previous version of the add-on (0.9.5).  This user has other reviews of this add-on.