Rated 1 out of 5 stars
It does not work on version 78.5.0. The author does not make updates, but it's a pity. There are such addons, so that it would be better for the authors to make them paid than to stop updating.This review is for a previous version of the add-on (2.0).
Identity Chooser has been supporting Thunderbird 78 since version 2.0. Please go into Thunderbird's addon manager and update your addons.
If you still have problems please open an issue at Identity Chooser's github: https://github.com/speedball2001/identitychooser-mx.