Disapointed Rated 3 out of 5 stars

Tabgroups menu is a nice and usefull tool but... I'm really, really angry cause I had sorted all my bookmaks and Tabgroups menu don't look at an existing folder with the same name when you "bookmark group" from his menu. Result: A big folder with thousands of bookmarks hard sorted for hours and hours... deleted and replaced by one with same name from a group, without any warning, all my work to do again from a backup. I can't understand how a so stupid case can be forgotten when a tools is designed !!!!!!!!!!!

This review is for a previous version of the add-on (0.9.1-signed). 

It doesn't replace or delete any folder. It creates a new bookmark folder. It existing folder already exists, there will be two folders with the same name. Firefox allows bookmarks folder with duplicate names.