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.