Gmail From Sorter is a script for Firefox, Chrome and Opera designed to make Gmail a little easier to use.
Gmail gives users the ability to send email using other email addresses they own. When doing this, their other email address will be listed as the sender instead of their Gmail address. This allows users to manage multiple email accounts from within Gmail. You can find instructions on how to set this up on Google’s website.
The only catch is that if you have more than a few such email addresses, searching through the list of email addresses in the From field becomes painful, because the list is unsorted. This is especially painful when you have a catchall email account set up, and need to be able to reply on 35+ email addresses, as I do.
This script simply sorts the list of email addresses in the From field, relieving all the pain in an instant. It even works on Google Apps Email, for those using custom domains.