I assume that post which are displayed in bold in the msg list panel are (supposed to be) unread. There is some confusion here…
A large fraction of my Inbox messages are deemed to be unread, whereas they are all read in the standard interface. The same goes for other folders. I suspect a message is considered unread if it was read in a mail client only and not via the web interface.
If using a synchronized/local index a message marked as read via IMAP is currently not shown as read in the webmail. It’s a known issue that will be fixed.
This confused me too, but I assumed it was indexing in the background catching up.
Also noticed that a few of the “unread” e-mails in the Runbox 7 inbox were actually in the deleted folder in the original interface - because I had deleted them previously.