The end-user interface for an ActiveX control often consists of an assemblage
of one or more constituent controls. Such an ActiveX control is sometimes called a composite
Constituent controls are controls that already exist in the programming environment,
and they can be intrinsic Windows controls or custom controls from Microsoft or other vendors.
You can then piece together a new custom control by taking parts of the features of the constituent
controls and adding your own custom functionality as well.
A special case of the composite control would be the control which contains
only one constituent and whose purpose is to enhance the functionality of the constituent
by implementing different methods, properties, and events.