anchor.diff:  ;;; XXX still needed?
   (defmethod add-output-record :after
       ((child updating-output-record-mixin) record)
  -  (declare (ignore record))
  -  (if (parent-updating-output child)
  -      (push child (children-updating-output (parent-updating-output child)))
  -      nil))
  +  (declare (ignore record child)))
   
   
   ;;; Prevent deleted output records from coming back from the dead.
  
positive.code:    (stream :accessor updating-output-stream :initarg :stream :initform nil
  	   :documentation "Capture the screen in order to restrict update to
  					visible records")
     (children-updating-output :accessor children-updating-output :initform nil
  			     :documentation "A list of updating-output records
  that are children (but not necessarily direct) of this record.")
     (parent-updating-output :accessor parent-updating-output
  			   :initarg :parent-updating-output :initform nil
  			   :documentation "A backlink to the
  
negative.code: 					record
  					&optional errorp)
    (declare (ignore record errorp))
    (let ((pcache (parent-cache child)))
      (delete-from-map pcache
  		     (output-record-unique-id child)
  		     (output-record-id-test child))))
  
  
  (defclass standard-updating-output-record (updating-output-record-mixin
  