Hidden Archive Prefs is a Thunderbird extension that will expose a hidden configuration option for the message archiving functionality, allowing users to choose if they want or not to keep the current folder structure when archiving an email.
Hidden Archive Prefs is an add-on designed to work with the Mozilla Thunderbird, from version 3.1 until 3.3 Alpha 1 Pre.
How to Install in Thunderbird:
1. Right-click the link below and choose "Save Link As..." to download and save the file to your hard disk.
2. In Mozilla Thunderbird, open Add-ons from the Tools menu.
3. Click the Install button, and locate/select the file you downloaded and click "OK".
· Mozilla Thunderbird