Review for Extra Folder Columns by Stevie N
Rated 5 out of 5 stars
Use these versions until Joey Minta (we're waiting ;-) will release an official update:
English: http://www.file-upload.net/download-2183180/extra_folder_columns-0.4-tb-en-USpatched.xpi.html
German: http://www.file-upload.net/download-2098433/extra_folder_columns-0.4-tbDE-patched.xpi.html
Smart folders are labelled correctly.
To create your own collections, you must have a Mozilla Add-ons account.