An object that provides access to all of the System Properties contained within an item in the Composition. Contained in the "systemPropertyList" property of objects that represent items in the Composition.
All of the following properties are read-only.
The object whose properties are being accessed.
Always returns null.
Returns the current value of the specified System Property. Can return null.<
Sets a new value into the specified System Property. The value can be set to null.