Wurdearring: 5 fan de 5 stjerren

I have been a happy user of copysend2current for many years. But now after a Windows 10 reinstall and adding copysend2current anew I can't get the dialog to pop up when I send a message. Any hints what may be missing?
I'm using Thunderbird 60.0 32 bit under Windows 10.

Dizze beoardieling giet oer in eardere ferzje fan de add-on (1.2.1).