[Dovecot] Dovecot on Qnap ts-439

[BeKi]

Hello,

I use Xdove 1.2 on my ts-409 together with IMAP/dovecot. I like to see 
the same folder structure on my different workstation (private/work ...).

I move the mails into the folder structure I created. That works fine. 
But since I use Xdove with IMAP I have the problem that my mailclient 
loads all mails I already stored in different folders again into the 
INBOX (some mails also multiple with subfolders). These mails are 
duplicates (or multiples) because I delete them all. The mails in my 
folders are still there.

Up to now I tried different mail clients. Thunderbird 2.x/3.x, Pegasus 
4.5, Outlook Express. All behave the same way, so I think it must have 
something  to do with the server.

The times when the clients loads the mails into INBOX are not regular 
intervals. It can be a day when this happens again or one week.

Maybe one of you heard about this and can give me hints where to look for.

Which configuration files shall I post to help debug?

Thanks, Bernd