Same here but it looks to me as though somebody decided that none of this was necessary if they could make Mail.app look like it does on the iPhone. Gone is all the customization you were used to at a mailbox level.
it has to be a bug.
really must be.
in addition to the lack of ability to drag the length of a field to make it bigger or smaller, there are other really wierd/missing things like: if you are the sender of the mail, not being able to have a To: field at all.
(yes you can see it in the message pane where the main body of the mail is displayed, but you cant see the To: field (in the case were you are the To: then the small icon "To" is fine...)
anyway, it isn't going to be left as is, there are too many things that are unfinished right now.
also, the time it takes to do a rebuild on an email folder, and the time it takes for Rules to be applied and the mail messages impacted to reappear is sooo long now.
thank god that (as many people have reported) missing mail (mail that was there but no longer is able to be seen) is actually this: it will appear if you shut down mail then open it up again, but then again only after a reboot sometimes.
i think there is something wrong with the way the so-called "envelopes" work and the total way that mail is tracked and kept track of.
but i am too timid to go into Library/Mail and delete the relevant envelopes. waiting for apple to fix this.
