GtkWidget::map
    
     This method maps a widget to the screen area it will take.  It is
     mostly used internally, being one of the methods that is called as
     part of the show()  routine. 
     It causes the "map" signal to
     be emitted by the widget, which in turn switches a flag causing the
     widget to be mapped.
    
    
     At the point of a widget's becoming mapped, the 
     GdkEvent GDK_MAP is
     triggered, causing the 
     "map-event" signal to also
     be emitted by that widget.  Use this signal to trigger functions
     that rely on the map event having occurred.
    
    
     See also: show() ,
               realize() .