UID Purge?

[Kevin]

Hi,

I've just migrated to Dovecot from cyrus-imapd, and I notice that when I 
move emails from one folder to another they appear to be automatically 
marked deleted (expected) and also purged (not expected). With cyrus, I 
am used to emails being marked deleted, but still existing until a 
manual purge (expunge).

Is this normal behaviour with Dovecot, and is it configurable?

Thanks.

Kevin.