Rated 5 out of 5 stars

Go to StartupMaster Add-on, click hypertext link MORE
Check "Quit if the master password dialog is closed"

This review is for a previous version of the add-on (1.6.1-signed.1-signed). 

Rated 5 out of 5 stars

Cancel button opens firefox instead of closing it. You didn't click yes at the popup "Would you like to quit Firefox if the password dialog box is canceled?" If you click no, when you click cancel or the red "X" the popup closes and firefox opens. Remove StartupMaster, reinstall and click yes at that prompt. Works as you want it to. -;)

This review is for a previous version of the add-on (1.6.1-signed.1-signed).