I have an IMAP server running on my notebook. I use for keeping my archives.
Folders contain 15000 to 35000 messages inside. There are 4 folders like this. (2012 inbox, 2012 sent, 2013 inbox, 2013 sent).
I understand that first time I setup this account on Kmail, it fetches the summary information for the messages. Disconnected mode is not selected as anyway the server is running on the same PC.
However, if I change folders and then go back to this IMAP folder, I see that the folder starts to be repopulated, taking an undefined amount of time. Even if the folder seems populated once and for all, if I sort somehow by date or sender, I can see that new messages are popping up every second or so.

Thunderbird caches this message summaries in a summary file and displays this to the user rather than going to the server and requesting list each time the folder is opened. Shouldn't Kmail do the same? It's now unusable as I can't wait each time to open the folder and wait for it to populate from the server or maybe from akonadi or its local cache, I don't know. What I know is that it's very slow to open folders with many messages inside, it repopulates messages when you return to that folder and this re-population does not seem to end quickly as new messages still seem to pop-up after many seconds.

Reproducible: Always

Steps to Reproduce:
1. Have a Dovecot IMAP server running on localhost with ~30k messages in folders
2. Add account to Kmail2
3. List folders and view message list
4. jump to some other folder, for example local folers
5. return to the IMAP folder and see that it is again populating the message list or not showing it instantly or the population process goes on despite long wait time.
Actual Results:  
Message list repopulated each time I visit the folder
Re-Population does not show a proper progress and messages seem to pop up even after long waiting times (for a server running on localhost)

Expected Results:  
Message list shall be obtained once when viewing the message list for the first time, then it shall be cached. 
The cache shall be used to build message list when switching to this folder again.
Kmail2 can even cache the "last view" and fetch remaining messages if user scrolls down or changes sort mode. (for even speeder UI feeling)

Ubuntu 13.04 up to date.