By default, the UserData property is empty. You can use the UserData property to associate any extra data to the current event. You can display the event's UserData as string on the body of the event, if the ShortLabel, LongLabel, ExtraLabel or ToolTip properties of the Event includes the <%=%6%> TAG. The RemoveEvent event notifies your application once an event is removed from the Events collection. You can use the RemoveEvent event to release any extra data that has been allocated to the event during creation. The UserData property of the Event, or for any other object is provided to let you associate any extra data to the object. For instance, the UserData property can hold any event related data that is not displayed, like a primary key of an event in database.