anchor.diff:                        ((:left) x1)
                         ((:right) (- x2 w))
                         ((:center) (/ (+ x1 x2 (- w)) 2))
  -                      (otherwise x1))  ;defensive programming
  +                      (otherwise x1)) ; defensive programming
                       (case align-y
                         ((:top) (+ y1 as))
                         ((:center) (/ (+ y1 y2 (- as ds)) 2))
  
positive.code: ;;
  ;; --GB
  
  (defclass 3D-border-mixin ()
    ((border-width :initarg :border-width :initform 2)
     (border-style :initarg :border-style :initform :outset)
  
negative.code:     (draw-bordered-polygon pane (polygon-points (bounding-rectangle (sheet-region pane)))
                             :border-width border-width
                             :style border-style)))
  
  ;;; Common colors:
  
  