Can someone please tell me why Outlook Express has started putting incoming emails into 'sub folders' all of a sudden. I get a mail from a sender, I open it, close it and go onto the next one. The following message from that sender then goes into a 'sub folder' under their original email. It never used to do this, and if their mail is a long way down the list, it is a pain in the butt to go find it. It used to be that all new mails would enter the list at the top, singly! I like it and want it that way. As far as I know, I have changed nothing.
 
I have looked thru the help section, and can find no reference to it, and this is the first time I ever recall it happening.