Über dieses Add-on
To select the Categorized Folders mode, use the left and right arrows in the folder pane to cycle through the modes until you see the proper mode. It should be before the All Folders mode.
More information is accessible at the project page on Mozdev.
* Cross-folder via the 'n' key does not switch to another folder unless the server it's in is expanded.
This is believed to be the first extension to create a new custom folder pane view. As such, feedback about bugs that may be a result of improper core code would be appreciated.