kmail - problems with next unread and message display

Hi,

I'm currently trying to switch over from T-Bird/icedove to kmail, however I 
encountered a few annoyances which I have so far found no remedy against.

I'm running Debian Squeeze (aka testing) right now, with kmail version 4.2.2-1 
(as might show up in the header of this email).

I've re-assigned the key to move to go to the next unread message to 'n' if 
that matters at all, overwriting the default of '+' and also the action for 
the old binding of 'n'. 

I'm using standard (online) IMAP as I don't want to mirror most of my mails to 
my local system with disconnected IMAP with my own server running dovecot. 
What happens quite often is that the inbox contains several new mails, I can 
start reading them by hitting 'n' again and again and then it seems to be 
stuck. Inbox is reported to contain a couple of unread mails, but 'n' won't 
move there. I need to click on another mail to make 'n' working again, 
although sometimes I have the feeling that I need to be 'above' the unread 
emails, to reach the next unread one as if there were no wrap-around.

I've tried different settings for aggregation and with the 'activity, threaded' 
or 'current activity, threaded' it happens more often than 'standard mailing 
list' one, however even there it happens quite often. Sorting is by least 
recent on top and by Date/Time of most recent subtree.

Another annoyance happening from time to time is that the email message is not 
displayed, i.e. the headers are displayed, but not the body of the email. 
Remedy here is to move to another email and going back again.

Overall not a 100% show-stopper, but rather inconvenient, especially when you 
have many, many emails a day.

Are these known problems, or is that something with my settings?

Any help appreciated.

Cheers

Carsten

PS: Please cc me for now as I'm still in the process of joining the list.