I opened the Event Frame for Motorcycle Tire production in the earlier exercise. Now I am unable to add outputs to it. The Add... pulldown is greyed out and will not let me add anything. At one point, I saw a message telling me the event frame was read only. I even added an Identity for my Windows ID in the AF database security so that I have all permissions. I still can't add anything. What do I need to do to add the Output Calculation?