All components which implement this service can
be integrated in a windowing environment. This service describes
the controller of the Smalltalk model view controller design.
You must set a model and a stub to the UnoControl before using
other methods. The implementation only allows the change of the
graphics (XView) if the window is not visible. The
change of the graphics in visible state should redirect the output
to these graphics, but this behavior is implementation-specific.
The change of data directly at the control may not affect the
model data. To ensure this behavior, modify the data of the model.