The ShellCt FCMD source code is an "empty shell" that can be used as a starting point for the creation of new control drivers. It supports only simple drawing of the body, title, and frame of the control. It also supports button-like behavior by using inversion to hilite the control. The source is included with the Inside FaceWare product.
ShellCt controls are also useful when a program needs to directly control a portion of a ViewIt window. In this case all or most messages from ViewIt to the control are intercepted and handled by a program override procedure (see "Override" topic in the ViewIt Guide for details).