Losing recipient when moving sent mails to another folder

Mails in my sent folder correctly show the name or email address of the recipient. However, if I move a sent mail to another folder that I have created on the server, the recipient contact details disappear and are replaced by my contact details as the sender.

About as much use as a chocolate fireguard in terms of scrolling through the folder list and identifying to whom a particular mail was sent. Is there a setting I have missed somewhere?

That’s pretty normal behavior. Only the Sent folder would show the recipient. Other folders would presumably contain mail sent to you. You may be able to customize the fields shown on a desktop client. I would not expect such an option to exist in K-9. If it does, hopefully someone will share how to access that setting. If it doesn’t, you might want to create a feature request.

Well, the other Android email clients on my phone - Aquamail and Fairemail, don’t have any problem in showing the recipient when I move a mail from sent to another folder, I don’t have to do anything special, the contact details are retained when the mail is moved. Hence my question.

A pity, because I very much like option in K-9 to designate folders as either 1st and 2nd Class. Oh well.