Hi,
The items to display controls what is shown if you click on an item, not what is shown in the calendar view. I am pretty sure that you are limited to the subject line.
As a workaround I tend to use rules attached to the appointment object to put the information that I would like to show into the subject, i.e.:
If FulfillmentAppointment IS NEW OR FulfillmentAppointment.StartTime WAS CHANGED OR FulfillmentAppointment.Client WAS CHANGED OR FulfillmentAppointment.FulfillmentAdvisor WAS CHANGED Then
FulfillmentAppointment.Subject='Conf #:'+FulfillmentAppointment.Client.ConfirmationNumber+AS_STRING(FulfillmentAppointment.StartTime,' - h:mm a')+' - '+FulfillmentAppointment.FulfillmentAdvisor.FirstName
Cheers,
Pete