ActiveX controls are self contained Windows controls that expose
their functionality via a COM interface. In OpenDCL, the ActiveX control
type is a container for the actual control that is being used. ActiveX
controls must be registered (usually during application installation) on
the system where they will be used. In addition to the OpenDCL specific
properties, most ActiveX controls expose custom properties, methods, and
events by publishing them in the control's type library or some other
form of documentation.