Version:            (using Devel)
OS:                Linux
Installed from:    Compiled sources

I usually process my emails just by clicking the "+" button to move to each next unread email. Often, opening next email takes noticeable time -- it could take a couple of second for a IMAP server across the globe, and for a fairly close server, still takes noticeable time.

I would be pretty cool if kmail could fetch, in background, the next unread email, so that "+" button can just render already-fetched email.