I've been playing with the latest RC beta and SVN versions for the past day or so and it's really a great client. The only thing it seems to be "missing" as an IMAP-aware MUA goes is support for private and public namespaces. Apparently I'm not the only one that noticed this though, as I found a reference to it on the Wiki
http://trac.roundcube.net/trac.cgi/wiki/Howto_Config.
I looked through the various code pages to see if anything can be done to rectify this, but it would seem that some re-work would be necessary, as the imap_root is being explicitly set (even if you leave the $rcmail_config['imap_root'] = ''; as a null value). Courier-IMAP has multiple namespaces (or imap roots), INBOX. and shared., both of which are at the top level. If you leave the imap_root as null, you get all subfolders at the same level as INBOX, which in and of itself is wrong, since they're below the INBOX. level. That requires setting imap_root to '.' or 'INBOX.'.
RC
can see the shared. namespace, if it's explicitly set as the imap_root or by putting it into the URL (i.e.
http://server/webmail/?_task=mail&_mbox=shared.Spam), but as you can imagine, this isn't ideal. If anyone out there has figured out a way for RC to display the shared. namespace in the folder list, a patch would be highly appreciated.
Thanks.