It would be nice if RC will support NTLM authentication. That will give a chance to make a friendship with Active Directory. Any plans re: NTLM support ?
RC authenticates directly with the IMAP server, that is a basic part of it so i dont think it would ever change.
So if IMAP server is integrated with AD by means NTLM or even GSSAPI RC has no chances to work with it unless some other auth methods used....
thats fine. you could modify something like the autologon plugin and use that to pick the AD details from the user and pass them into roundcube to perfrom the login and then the user would never see the login page.