Review for Manually sort folders by paddingtonbear
Rated 5 out of 5 stars
It does work. Download it. Then go to tools>add ons and type in "manually sort folders"
Restart Thunderbird. 
Go to tools and in the list you will find >Manually sort folders
Click on it and you can sort the folders. 
Then restart. 
Thank you very much.  Love it.
To create your own collections, you must have a Mozilla Add-ons account.
 
    