I start with entering a contact not precent in my contacts in the To field of a new message.
Adds it to my contacts by right click (lägg till kontakt), last entry.
Donald is now present in my contacts.
If I right click again, (Donald is now precent in my contacts) add to contacts is still active (lägg till kontakt) at the bottom.
If I choose an other contact already precent in my contacts I get the option to edit contact (Redigera kontakt) at the bottom.
I think it should be possible to add a contact and then edit it in this situation.