anchor.diff:           (d (text-style-descent (pane-text-style pane) pane))
            (m0 2)
            (h (+ a d m0 m0)))
  -    (cond ((sheet-children pane)
  +    (cond ((and (sheet-children pane)
  +                ;; ### this other test below seems to be neccessary since
  +                ;;     somebody decided that (NIL) is a valid return value
  +                ;;     from sheet-children. --GB 2002-11-10
  +                (first (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
  
positive.code:               :reader label-pane-label-alignment)
     (background :initform *3d-normal-color*)
     )
    (:documentation ""))
  
  (defmacro labelling ((&rest options) &body contents)
  
negative.code: 
  (defmethod handle-repaint ((pane lowered-pane) region)
    (declare (ignore region))
    (with-slots (border-width) pane
      (multiple-value-call #'draw-bordered-rectangle* pane (bounding-rectangle* (sheet-region pane))
                           :style :inset
                           :border-width border-width)))
  
  ;;; RESTRAINING PANE
  
  