Under Thunderbird 60.4.0 for Mac, this doesn't do ANYTHING. I can open and adjust its SETTINGS, but it NEVER offers the option to COPY. Thunderbird REPORTS copying to SENT, but copysent2current never intervenes. What's up???
It WAS working nicely in 5x.y versions I had.
This review is for a previous version of the add-on (1.2.3).