I recently started using Zimbra Desktop to access my Gmail account. I'm very happy with it on the whole except for one major problem: the spam filter. It has a tendency to grab many legitimate e-mails in my inbox and move them to the Junk folder in Zimbra Desktop. What confuses me the most about it is that most of the e-mails it classifies as "spam" are from the e-mail contact who e-mails me the most frequently. I've tried training the filter by clicking the Not Spam button. I've tried syncing the Junk folder with my Gmail account's Spam folder in the hopes that Zimbra Desktop would then leave it alone. I've tried adding multiple filters with the action "Keep in Inbox" with "Do not process additional filters" checked. But none of it works. I've confirmed that this is definitely a problem with Zimbra Desktop and not my Gmail account (and can elaborate on this if anyone wants me to). So my question is:

How can I disable the spam filter completely in Zimbra Desktop?

I have no aversion to delving into any of the files that make up the guts of the program, as long as it will get this problem fixed. If I can't correct it, I'm going to have to abandon Zimbra Desktop, which I'd hate to do since I find it to be otherwise nearly perfect. I'm running Zimbra Desktop version 7.2.2 on OSX 10.6.8. Thanks in advance for any help.