Outlook default folder sent itmes

Dears,

Currently, I’m using an IMAP email account with Outlook 2016. I would like to have my sent items in a different IMAP folder.

In menu “options” in the “compose an email”-menu, I can change the folder, but as soon as I have sent the email, the folder changes back to its default.

Any idea, how I can change the sent items folder definitely?

many thanks for all your comments and advise, cheers