Relay Folders av Samuel Risner

This extension allows you to use folders and tags by saving their data in the email masks name. This limits the extension in the following ways: you need to manually save the folders and tags (by copying the displayed text to the end of the masks name) and you are limited to an overall amount of 50 characters for the masks name and the folder and tag information.
To apply tag and folder settings a page-reload is required.