Review for StartupMaster by c_eren
Rated 4 out of 5 stars
It is good because it does not let you open Thunderbird unless you enter your master password. However, you have to tick the associated box first. It is on Thunderbird > add-on title.
This review is for a previous version of the add-on (1.6.1-signed.1-signed).To create your own collections, you must have a Mozilla Add-ons account.