The Icon class is derived from UI_VObjCollection
(what might not have been necessary). An Icon must be
supplied with a bitmap and optionally with a popup
menu. The menu will be registrated for the parent
of the icon, which must be a CompositeVObject
or an IconWindow.  An Icon consits of the bitmap
and a label.  As soon as the icon is being selected
the background and foreground colour of the label
and the bitmap invert. There are methods to ask
for the selectivity state. If the icon has been supplied
with a menu, the menu appears, after the rigth mouse
button has been pressed (at the current cursor position).
If an IconWindow is used as parent, the Icon will be 
positioned automatically.