Rated 5 out of 5 stars

Great add-on! I had been using the 'Quicker Filer' add-on [https://addons.thunderbird.net/en-us/thunderbird/addon/quicker-filer/], but since the project was abandoned and it was about time for me to update Thunderbird to the newest version, I decided to use Nostalgy++ instead.

It does all that Quicker Filer does, and better.
There is only one thing I'm missing dearly though:
Quicker Filer would also provide a folder completion box inside the message compose/reply window. The message would then be automatically saved to the selected folder after the 'Send' button is pressed, thus saving me from having to go back to the 'Sent Mail' folder and saving the message using the 's' key.

Also, while having a folder selected in the folders pane, and doing any of the following, the folder completion box inside the resulting compose window would automatically be populated with that folder:
- click on 'Write' button to compose a new message inside that folder.
- click on 'Forward' or 'Reply' button of a message inside that folder.

Cheers.

Léirmheas ar leagan níos sine den bhreiseán seo (2.3.1). 

I will think about that.

would this be interesting:

reply to a message in inbox. On send, move original message and reply to the folder of a rule? S would not be necessary for either of them