Review for Folder Pane View Switcher by ivica_zivkovic
Rated 5 out of 5 stars
Excellent add-on, even with this issue of not starting with Thunderbird. It actually does not need to be re-installed, it is enough to 'remove' it and then 'undo', so literally two clicks, and it reappears.
This review is for a previous version of the add-on (4.0.2).To create your own collections, you must have a Mozilla Add-ons account.