Rated 4 out of 5 stars
This is very good addon, but I have faced with a problem in one particular case:
I have created new search folder in Thunderbird and have included there all messages from "Inbox" and "Sent Items" (Edit->Find->Search Messages->Save As Search Folder, Give it a name, Choose "Inbox" and "Send Items" folders, select "Match all messages", press OK). And ThreadKey works incorrectly in this new folder - no + and dots appeared :-(
Could anybody give and advice how to solve this problem?
This is Thunderbird bug 379806 which is fixed in Thunderbird 3.0.