Review for Tag Toolbar / Tag Popup by Reiner Block
Rated 3 out of 5 stars
Tested "A quick fix for XML parsing error" of Mathieu on November 13, 2015 and it worked nicely.
Thanx to Mathieu because it seems that Ogi no longer supports his Add-on.
Pity is that still the configuration dialog does not work properly. It's not possible to add tags to groups or move tags in a group up and down.
To create your own collections, you must have a Mozilla Add-ons account.