Before doing anything to an object, the MHEG-5 engine must prepare it. Preparing an object typically entails retrieving it from the server, decoding the interchange format and creating the corresponding internal data structures, and making the object available for further processing. The preparation of an object is asynchronous; its completion is signalled by an IsAvailable event.
All objects that are part of an application or a scene have a RunningStatus, which is either true or false. Objects whose RunningStatus is true are said to be running, which means that they perform the behaviour they are programmed for. More concretely:
The MHEG-5 mix-in class Interactible groups some functionality associated with user interface-related objects (Slider, HyperText, EntryField, Buttons). These objects can all be highlighted (by setting their HighlightStatus to True). They also have the attribute InteractionStatus, which, when set to true, allows the object to interact directly with the user, thus bypassing the normal processing of UserInput events by the MHEG-5 engine. Exactly how an Interactible reacts when its InteractionStatus is true is implementation-specific. As an example, the way that a user enters characters in an EntryField can be implemented in different ways in different MHEG-5 engines.
At most one Interactible at a time can have its InteractionStatus set to True.