GtkWidget::queue_draw
    
     This method is the one to use if you need to force a widget to
     redraw itself.  Put it into a callback function and determine
     an appropriate signal to trigger the redraws. 
     queue_draw()  creates an expose
     event, in most situations.
    
    
     In the event that this method does not have the desired effect, try
     calling queue_resize()  instead. 
     If that also fails, you will need to resort to calling 
     hide()  followed immediately by 
     show()  in the callback.