anchor.diff:  
   (defun scsu-change-to-window (state window)
     (declare (type window-index window))
  +  ;; update LRU entry
  +  (let ((timestamp (incf (scsu-state-current-timestamp state))))
  +    (setf (scsu-state-timestamp state window) timestamp))
     (setf (scsu-state-active-window-index state) window))
   
   (defun scsu-define-window (state window offset)
  
positive.code:     :initform +default-positions-for-dynamically-positioned-windows+
      :accessor scsu-state-dynamic-window)
     (active-window-index :initform 0 :accessor scsu-state-active-window-index)
     (fix-dynamic-window :initarg :fixed-window :initform *scsu-state-default-fix-dynamic-window*
  		       :accessor scsu-state-fix-dynamic-window
  		       :type boolean)))
  
negative.code:   (setf (lookup-dynamic-window state (scsu-state-active-window-index state))
  	offset))
  
  (defmethod scsu-state-timestamp (state window)
    (declare (type window-index window))
    (aref (scsu-state-timestamp-vector state) window))
  
  (defmethod (setf scsu-state-timestamp) (val state window)
    (declare (type window-index window))
    (setf (aref (scsu-state-timestamp-vector state) window) val))
  
  (defmethod scsu-state-reset ((state scsu-state))
    (slot-makunbound state 'mode)
    (slot-makunbound state 'dynamic-window)
    (slot-makunbound state 'active-window-index)
    (slot-makunbound state 'timestamp-vector)
    (slot-makunbound state 'current-timestamp)
    (shared-initialize state t))
  
  
  