[Dovecot] cannot delete emails in inbox

[JANE CUA]

I am working on upgrading our current squirrelmail and replace uw-imap with dovecot.  I have what looks like a successful installation.  My current setup is: 
Centos 5.2
sendmail 8.13.8
dovecot 1.1.17 (imap)
squirrelmail 1.4.17

I can send and receive email fine.  However when I try to delete an email in my Inbox, it doesn't get deleted.  It only sends a copy to the Trash folder.  But the email is still in the Inbox.  I can purge and delete the contents in my Trash and Sent folder, no problem.  I am not sure if this is a Squirrelmail issue or a Dovecot issue.  Please advice.  Thank you -- Jane