a nice new Classic Address Sidebar, like the Contacts Sidebar, but this works in 52.X and later !! Niiccee' , and Thank you very much ! And Thank you very mutch for bring back, like previous speaker said .. big fad thumps up !! And you be added on Watch : https://github.com/shimamu/thunderbird-custom-address-sidebar
edit/info: i have make a update with a X.X.1 version with german language files on my blackysgate.de/files
This review is for a previous version of the add-on (2.4).