Allow same folder for Sent and Archive

I want to archive all emails to the same place. Specifically I want my “sent mail” to be archived in the “Archive”. This is simple enough in other mail clients. There’s even a tick box option for it in evolution.

However in mailspring, it seems the drop downs for Inbox/Sent/Drafts/Spam/Archive/Trash are all mutually exclusive. You can’t have the same send folder as Archive. When I set my sent mail to my archive directory the “Archive” drop down is set blank.

(Originally posted by couling on GitHub.)

I’ve checked: the described behavior is in Mailsync, if anyone wants to go digging for it.