Some kitControl components are not based on “simple control points” (ControlPoint). You cannot add any extensions to these components. If you try, you receive an “illegal parent” error message.

Components in kitControl that cannot receive extensions include:

You can quickly tell if a kitControl object can receive an extension, by seeing if it has the frozen “ProxyExt” (proxy extension). See this by expanding the object in the kitControl palette, Nav tree or viewing the object’s property sheet.If present, you can add other extensions (providing they are the correct type), for example “BooleanChangeOfValue” history extension for a Logic-type object, and so forth.Also, note this is the only use for the proxy extension in a kitControl object (its value is always “null”)—only control points can be proxy points.