Rated 5 out of 5 stars

per Alexander Ihrig el set. 14, 2020 ·

Really perfect re-implementation of this missing/removed feature in Thunderbird 78 using the collapsed="true" attribute. And the best is, that it supports other extensions, which add buttons to the toolbar (like my "Allow HTML Temp" addon).

This review is for a previous version of the add-on (2.0.4).