Hi,
First off just want to say congrats on such a fantastic web app :)
It would seem that on connection to a new imap account RoundCube does not create the trash or 'Deleted Items' folder - meaning I can't delete anything.
I had to connect with Thunderbird, which automatically created it.
When setting RoundCube up, I didn't have support for some of the optional php stuff and I haven't set up sending mails yet, in case that has anything to do with it.
Thanks
OK I found it, it's just a config change in main.inc.php
// automatically create the above listed default folders on login
$rcmail_config['create_default_folders'] = TRUE;
:)