Keep in mind that new mail is not a real folder like the others. It is just a visual representation of the *.cnm files when doing pop3 or local delivery. The newly arrived messages are always added to the top and any with urgent marked on top of the others also. Once you resort or close and open new mail they are then sorted. The new mail in an IMAP mounted box depens on the inbox order on the server. Real folders, *.pmm and *pmi pairs are sorted according to preferences and those are sticky and when closed and opened remain the same as they were.
Keep in mind that new mail is not a real folder like the others. It is just a visual representation of the *.cnm files when doing pop3 or local delivery. The newly arrived messages are always added to the top and any with urgent marked on top of the others also. Once you resort or close and open new mail they are then sorted. The new mail in an IMAP mounted box depens on the inbox order on the server. Real folders, *.pmm and *pmi pairs are sorted according to preferences and those are sticky and when closed and opened remain the same as they were.