Fixed Mel's comments regarding Event page

5) Add new event
5.1) Notification list: x (explain : remove)
5.2) If the event had already delivered, add new comment at the bottom
e.g. "This event had already processed"
5.3) On the modify event page, when the 'save' button is disabled,
change the button name: 'cancel' -> 'return'
However, if the 'save' button is enable, it should have 'cancel' button.
5.4) If 'surprise' button is clicked, 'birthday owner' and 'birthday
message' become disable.