GmailUI – allows specifying multiple constraints, such as To and Subject, when searching messages (that is, it’s not about UI at all) Duplicate Contact Manager – does what it says, but is said not to work well for 1000+ contacts, and merging duplicates requires copy/paste rather than clicking a checkbox. After the Thunderbird has been Under Incoming Server, enter 'mail. A WebExtension experiment is an additional API that is shipped with your WebExtension. Building a Thunderbird extension Step-by-step explanation on how to build an Start by reading the tutorial and learn how to build a Thunderbird extension.
