Virtual uid and gid-mapping for mailserver to fit to sites system_user/group
At this time mailbox-quota doesn't increase to clients quota so it is necessary to add a quota to all mailboxes to avoid overfilled servers. Since there is added a "client" group to the system when adding a client and a "web"-user when adding a site, it would also be possible to use virtual_gid_map and virtual_uid_map for postfix and reading gid and uid from databasetable mail_user instead of using static 5000:5000
Additional there should be a checkbox on mail-server-configuration to enable/disable this behaviour.
(I'm already working on this issue and will suggest the necessary changes after I'm sure that it is working)