While Feng Office's email feature (FOe) is generally very good, there are a couple of awkward aspects to it.
FOe does not support message folders in the standard sense. The "workspace" feature provides functionality that is similar and in some ways better, but it's not yet clear whether it is a good practical replacement.
For one thing, folders in IMAP accounts are not mapped to workspaces. You can configure which folders to include when mail is being fetched, but mail from folders is mixed together at download time without any further tagging or workspace-assignment. In theory, you could set up a separate IMAP account for each folder, but this could be quite tedious for more than a very small number of folders, and would not keep your FOe folder list synchronized with what was available from your IMAP account.
FOe does not support importing or exporting of email messages. To be fair, this is a common omission in email clients, but most open-source clients at least support a standard message storage format such as Maildir or mbox; FOe's messages are stored in the database server.
To get around this, it may be possible to simply set up a mailbox folder (on a POP3 server MDA) into which Maildir or mbox files can be dropped, and then have FOe retrieve those messages via POP3. Again, the folder structure will be lost, but at least the messages can be imported and (later) manually re-categorized. I have yet to actually try this... plan to report back if it works or not. --Woozle 22:15, 20 May 2010 (UTC)