Why the removed flag will be resumed after re-sync with MS Exchange server (2010)

Question

Dear Sir:
     I had a big problem using Lion mail application. I like the program since it's quite simple and useful. But this problem makes me not able to work with Lion mail program continaully.
     In Lion mail, I import my office mail account which based on MS Exchange server 2010. I just found some mails (sorry I cannot fina any rule) which ever be flagged, when I try to un-flag them. The flag status will come back after re-sync with mail server. But the status doesn't happen with all mails I had. One thing I can confirm is, the "specific" mail doesn't be marked with any status after I checked them using Outlook application (both Mac Office 2011 or Windows Office 2010). Have you ever received similar feedback? Please help me to resolve this issue ASAP. Thank you.
-Joseph

Answer 1

When the original message is accessed using IMAP, the reply method uses the information in the
IMAP ENVELOPE to determine where to send the reply. It first looks for the Reply-To address
in the ENVELOPE, then the From address.
Interestingly, when not using IMAP, the getFrom method returns the Sender header if the From
header is empty. The IMAP-specific code doesn't do that, although perhaps it should.
It would be interesting to compare the ENVELOPE data from the protocol trace in the two cases.
The ENVELOPE data will follow this syntax:
envelope     = "(" env-date SP env-subject SP env-from SP
          env-sender SP env-reply-to SP env-to SP env-cc SP
          env-bcc SP env-in-reply-to SP env-message-id ")"
So it's the first three address fields after the Subject that are relevant. If the From and Reply-To
fields are NIL, but the Sender field has a valid address, let me know. I should probably fix the
IMAP provider to fall back to the Sender field if the From field is missing.