anchor.diff:    (declare (ignorable thickness contents))
     (with-slots (user-width user-min-width user-max-width
                  user-height user-min-height user-max-height)
  -      spacing
  -    #+nil(setf user-width  (max (or thickness 0) (or user-width 0)))
  -    #+nil(setf user-height (max (or thickness 0) (or user-height 0)))))
  +      spacing))
   
   (defmethod compose-space ((pane spacing-pane) &key width height)
     (declare (ignore width height))
  
positive.code:                                    child-height)
                                  (- child-height viewport-height)
                                  vertical-scroll))))
        (scroller-pane/update-scroll-bars (sheet-parent pane))
        #+NIL
        (scroll-extent child
                       (if (> (+ horizontal-scroll viewport-width)
                              child-width)
                           (max 0 (- child-width viewport-width))
                           horizontal-scroll)
                       (if (> (+ vertical-scroll viewport-height)
                              child-height)
                           (max 0 (- child-height viewport-height))
                           vertical-scroll)))))
  
  ;;;;
  ;;;; SCROLLER PANE
  
negative.code:                 :height     (+ (space-requirement-height c) ys)
                  :min-height (+ (space-requirement-min-height c) ys)
                  :max-height (+ (space-requirement-max-height c) ys))))
            res)))))
  
  (defmethod allocate-space ((pane table-pane) width height)
  