Mac Mail revisited

I can't believe I'm only a2k participant having this difficulty with Mac Mail. If you haven't encountered it yourself I don't expect a response but if you have and can tell me how to restore it to default state, I'd like to hear from you when you have the chance

In Mac Mail Sent and Trash (and only occasionally Inbox) don't work the same way they did, that is to list each and every message. Since Mac's last major revision, in these listings it combines related messages--apparently those having the same title--into a single entry, often making it difficult or next to impossible to find the one desired

Evidently then the only way around it is never to use the same title on two different messages, a requirement so stupid and next to impossible it makes one wonder about the IQ of guy who write Mac's editing routines

Or is it that I'm alone here, that I've brought this about with a single inadvertentkeystroke. (Testimony to the noted incompetence and typical of these PC "experts" was their inability to recognize misspelling in the foregoing sentence as two words)

Help, anyone else whom Mac so tortures, with many thanks at least for reading this posting