Manually Sort Folders is a Thunderbird extension that allows you to manually sort your folders in the folder pane, thus providing a fix for bug 193314. Thunderbird always sorts the folders in a given account alphabetically. Sometimes (especially when using Gmail+IMAP) there are many folders for an account, and being able to sort these folders to put the most important ones on top would be useful. This extension allows you to do just that.
Additional features include being able to use a better sort function that takes into account Unicode control characters (Thunderbird ignores them by default), allowing you to customize your Gmail labels with Unicode characters instead of manually setting a sort order. Subfolders can be sorted too.
Newer features include sorting accounts and choosing the startup folder.