Rated 5 out of 5 stars

I would reckon that one could start to regard this addon as superfluous if you use the latest versions of Thunderbird (I use v45.0). You can activate moving of mails to a particular folder with 'After Sending' in the filters. Problem is, as I have encountered, it does not always do that. Instead some messages for some addressees end up in the 'Sent' folder. This addon actually fixes them!