Outlook and IMAP Flags

Hi

I've tried searching the internet, but the only thing I can find is a post on a MIcrosoft forum where a Microsoft reps claims flags are not supported on IMAP (I thought it was an RFC3501 feature ?).

Anyway, I have a user who has Outlook/Windows on desktop and iOS (iPhone/iPad) for remote.

On the iOS devices, the user can happily set flags against messages with zero issues.  And indeed, when they set these flags, they are shown in Outlook.

However if they attempt to set the flag in Outlook, nothing happens. Outlook continues showing the message as if it was unflagged.

Any ideas ?

Laura