anchor.diff:  (defgeneric container-show-recursive (container))
   
   (defmethod container-show-recursive ((container container))
  -  "Recursively shows any child widgets except widgets explicit hidden during construction."
  +  "Recursively show any child widgets except widgets explicit hidden during construction."
     (labels ((recursive-show (widget)
   	     (when (typep widget 'container)
   	       (if (not (user-data-p widget 'show-recursive-p))
  
positive.code: (defgeneric (setf container-children) (children container))
  
  
  (defmethod shared-initialize ((container container) names &rest initargs 
  			      &key child children child-args 
  			           (show-children nil show-children-p))
    (declare (ignore child children))
    (when show-children-p
      (if (not show-children)
  	(setf (user-data container 'show-recursive-p) nil)
  
negative.code:      nil)
      (list
       (let ((list nil))
         (container-foreach container
  	#'(lambda (child)
  	    (push (funcall func child) list)))
         (nreverse list)))
      (t
       (let ((seq (make-sequence seqtype (container-length container)))
  	   (index 0))
         (container-foreach container
  	#'(lambda (child)
  	    (setf (elt seq index) (funcall func child))
  	    (incf index)))
         seq))))
  
  (defmethod container-all-children ((container container))
    (let ((internal ()))
      (container-forall container 
       #'(lambda (child)
  	 (push child internal)))
      (nreverse internal)))
  
  (defmethod container-internal-children ((container container))
    (let ((public-children (container-children container))
  	(all-children (container-all-children container)))
      (loop
       for child in all-children
       unless (find child public-children)
       collect child)))
  
  (defmethod (setf container-children) (children (container container))
    (dolist (child (container-children container))
  