anchor.diff:    (major-spacing x-spacing y-spacing)
     (minor-spacing x-spacing y-spacing)  )
   
  - (defmethod xically-content-sr** ((pane box-layout-mixin) child)
  + (defmethod xically-content-sr** ((pane box-layout-mixin) client)
      (let (p)
  -     (cond ((constraint-slot pane child 'fill-p)
  -            (let ((child-space (compose-space child)))
  +     (let ((sr (if (box-client-pane client)
  +                   (compose-space (box-client-pane client))
  +                   (make-space-requirement :width 0 :min-width 0 :max-width 0
  +                                           :height 0 :min-height 0 :max-height 0))))
  +       (cond ((box-client-fillp client)
                 (make-space-requirement
  -               :major     (space-requirement-major child-space)
  -               :min-major (space-requirement-min-major child-space)
  +               :major     (space-requirement-major sr)
  +               :min-major (space-requirement-min-major sr)
                  :max-major +fill+
  -               :minor     (space-requirement-minor child-space)
  -               :min-minor (space-requirement-min-minor child-space)
  -               :max-minor (space-requirement-max-minor child-space))))
  -           ((setq p (constraint-slot pane child 'fixed-size))
  -            (let ((sr (compose-space child)))
  +               :minor     (space-requirement-minor sr)
  +               :min-minor (space-requirement-min-minor sr)
  +               :max-minor (space-requirement-max-minor sr)))
  +             ((setq p (box-client-fixed-size client))
                 (make-space-requirement
                  :major     p
                  :min-major p
                  :max-major p
                  :minor     (if sr (space-requirement-minor sr) 0)
                  :min-minor (if sr (space-requirement-min-minor sr) 0)
  -               :max-minor (if sr (space-requirement-max-minor sr) 0))))
  -           (t
  -            (compose-space child)) )))
  +               :max-minor (if sr (space-requirement-max-minor sr) 0)))
  +             (t
  +              sr) ))))
   
    (defmethod box-layout-mixin/xically-compose-space ((pane box-layout-mixin))
      (let ((n (length (sheet-enabled-children pane))))
        (with-slots (major-spacing) pane
          (loop
  -           for child in (sheet-enabled-children pane)
  -           for sr = (xically-content-sr** pane child)
  +           for client in (box-layout-mixin-clients pane)
  +           for sr = (xically-content-sr** pane client)
              sum (space-requirement-major sr) into major
              sum (space-requirement-min-major sr) into min-major
              sum (space-requirement-max-major sr) into max-major
  
positive.code:          (d (text-style-descent (pane-text-style pane) pane))
           (m0 2)
           (h (+ a d m0 m0)))
      (cond ((sheet-children pane)
             (let ((sr2 (compose-space (first (sheet-children pane)))))
               (multiple-value-bind (right top left bottom) (label-pane-margins pane)
                 (make-space-requirement
  
negative.code: 
  ;;; LABEL PANE
  
  (defclass label-pane (single-child-composite-pane  permanent-medium-sheet-output-mixin)
    ((label :type string :initarg :label :accessor label-pane-label)
     (alignment :type (member :bottom :top)
                :initform :top
  