Comment 44 for bug 1085

There are actually two extensions that provide this functionality in different ways:

AddressContext
https://addons.mozilla.org/en-us/thunderbird/addon/addresscontext/

RecipientBox
https://addons.mozilla.org/en-US/thunderbird/addon/recipientbox/

Unfortunately, they are both so outdated that AddressContext only works for versions up to TB2 (although a user comments that (s)he was able to get it to function for TB5 with a workaround), and RecipientBox has been "disabled by an administrator" while only working for up to TB3.

In order to be able to use at least one of these great and very useful extensions, I am still using TB3.

Will someone please incorporate this functionality into Thunderbird?