Need clarification on the way mail "redirect" works

Can someone clarify / confirm the way mail "redirect" works ?

Here is what just happened to me. Last week I had sent a notification to a list of correspondants. Today I had to send the same notification, with a few corrections to another correspondant. So I used the redirect method.

I then got a window with the original email, with empty TO: and CC: boxes. I made a few changes in subject and content, filled in the new recepients (TO and CC) and sent the mail.

Then the receiver replied asking why I had sent the mail to that list of other correspondants that I had sent the original email to.

When I checked my received copy of the mail (I always ask for a BCC copy of all mails I sent) as well as the copy in the SENT folder, I saw that both still had the full list of the original recipients. The mail headers look like this:

Resent-From: (my email)

From: (my email)

Subject: (new updated subject)

Date: (Original date)

Resent-To: (New recipients)

To: (Original recipients)

Resent-Cc: (New CC recipients)

Cc: (Original recipients)

Can someone confirm that the email was actually resent to the original TO and CC lists as well as the new recipients? I think it did not since I did not hear from any of those recipients about that mail, but I would like to be sure that the redirected mail is ONLY sent to tne NEW recipients (not the old).

The other concern (even if that mail was not resent) is that the new recipients are able to see the original recipients. They should not have been able to see them.

Finally, the mail was sent using the original date, not the new date. This makes the email look like an old mail.

I was actually thinking that the REDIRECT function worked like the "EDIT AS NEW" function in Thunderbird which allows me to take any email and modify it (including recipients and content) as a basis for a new mail, with all traces of previous recipients removed.

Finally, is this the way redirect is expected to work ?

Thanks

Albert