till wrote:
great idea of course, but I am not sure if sorting is actually part of the standard, I tried to find appropriate RFCs but were not too successful. If it is not part of it I personally wouldn't want to support something like that.
It's a draft extension: http://tools.ietf.org/html/draft-ietf-imapext-sort-19
The Internet mail consortium keeps a list of IMAP extensions at: http://www.imc.org/ietf-imapext/
Bob