anchor.diff:  ;;;; Layout Utilities
   
   (defun layout-child (child align-x align-y x y width height)
  -  "Allocates space to a child of a pane. 
  +  "Allocates space to a child of a pane.
      x, y, width, height designate the area of available space.
      align-x, align-y name the desired child alignment.
      If the child does not have enough strechability to cover all of the
  
positive.code:     (setf user-min-foo (space-requirement-min-width
  			(make-space-requirement
  			 :width (spacing-value-to-device-units pane foo)))))
  	    
    ;; when the user has no idea about the preferred size just take the
    ;; panes preferred size.
    (setf user-foo (or user-foo foo))
  
negative.code: (defclass scroller-pane (composite-pane)
    ((scroll-bar :type scroll-bar-spec ; (member t :vertical :horizontal nil)
                 ;; ### Note: I added NIL here, so that the application
                 ;; programmer can switch off scroll bars alltogether.
                 ;; The spec though has it neither in the description of
                 ;; SCROLLER-PANE, nor in the description of
                 ;; MAKE-CLIM-STREAM-PANE, but in OPEN-WINDOW-STREAM.
  