Howto stop reinitialization of manually terminated IMAP downloads?

Hello

I'm running Kontact Version 4.3.4, as supplied by Debian unstable and 
connect to a self-administrated Kolab 2.2.3. While the groupware-specific 
folders are handled as disconnected IMAP (as required), email is IMAP. My 
Inbox holds thousands of mails in a complex folder structure.

Recently, I needed to search for some string through my email and 
accordingly kontact/kmail started to download all email for searching. 
Download got stuck and I terminated the remaining queued folder-specific 
transfer jobs. Now I have the problem, that whenever I do anything that 
requires downloading messages (like copying a folder to another location), 
kontact/kmail starts downloading all message content again ...

Is there any way I can clear the downloading queue that is obviously 
preserved somewhere?

Thanks for any hints, Joh