Do you know of a compatibility issue between the Salesforce Zimlet and Internet Explorer 8? When I check the boxes "Show 'Send & Add' button in mail compose toolbar" and "Login to Salesforce when Zimbra is launched", they do not get saved. It says they're saved, but the "Send & Add" button doesn't show up in a new email message. When you go back to the Zimlet, the check marks are gone.
This all works fine in Firefox 11 and IE9. I also tried compatibility mode in IE8. I couldn't find any mention of this in the Zimbra Wiki. We have Zimbra version 7.1.2_GA_3268 (build 20110804120428)