We're having an issue with the zimbra calendar that is baffling me. It is only with one user, however it's the president of the organization and he has a lot of meetings and events to manage. He is using the latest version of Firefox and the Ajax version of Zimbra on a PC running XP.

When invited to a calendar event it appears the option to "accept" is ghosted out, and the event shows up on the calendar semi transparent. So when he tries to sync to his iPad the even wont show up on his calendar. Other users are able to accept the invite and it is added to their calendars normally.

Any ideas would be greatly appreciated.