anchor.diff:       :allocation :instance
        :accessor widget-child-slots
        :type container-child)
  -    (parent-window
  -     :allocation :virtual
  -     :getter "gtk_widget_get_parent_window"
  -     :setter "gtk_widget_set_parent_window"
  -     :accessor widget-parent-window
  -     :type gdk:window)
       (window
        :allocation :virtual
        :getter "gtk_widget_get_window"
  +     :unbound nil
        :reader widget-window
        :type gdk:window)
       (state
  
positive.code:      :setter "gtk_widget_set_child_visible"
       :accessor widget-child-visible-p
       :initarg :child-visible
       :type boolean)))
       
    ("GtkContainer"
     :slots
  
negative.code:      :allocation :virtual
       :getter "gtk_widget_get_colormap"
       :setter "gtk_widget_set_colormap"
       :unbound nil
       :initarg :colormap
       :accessor widget-colormap
       :type gdk:colormap)
      (visual
       :allocation :virtual
       :getter "gtk_widget_get_visual"
       :unbound nil
       :reader widget-visual
       :type gdk:visual)
      (direction
  