anchor.diff:        (note-tab-page-changed layout page))))
   
   (defmethod note-tab-page-changed ((layout tab-layout) page)
  -  nil)
  -
  -;;; GTK+ distinguishes between children user code creates and wants to
  -;;; see, and "internal" children the container creates and mostly hides
  -;;; from the user.  Let's steal that concept to ignore the header pane.
  -(defgeneric internal-child-p (child parent))
  -
  -(defmethod internal-child-p (child (parent tab-layout))
     nil)
   
   (defun page-successor (page)
  
positive.code: 
  (defmethod sheet-disown-child :before ((parent tab-layout) child &key errorp)
    (declare (ignore errorp))
    (unless (internal-child-p child parent)
      (let* ((page (sheet-to-page child))
  	   (current-page (tab-layout-enabled-page parent))
  	   (currentp (equal child (tab-page-pane current-page)))
  	   (successor
  	    (when currentp
  	      (page-successor current-page))))
        (setf (slot-value parent 'pages) (remove page (tab-layout-pages parent)))
        (when currentp
  	(setf (tab-layout-enabled-page parent) successor))
        (setf (tab-page-tab-layout page) nil))))
  
  (defun sheet-to-page (sheet)
    "For a SHEET that is a child of a tab layout, return the page corresponding
  
negative.code: 	(move-and-resize-sheet child 0 y width (- height y))
  	(allocate-space child width (- height y))))))
  
  (defmethod clim-tab-layout:note-tab-page-changed
      ((layout tab-layout-pane) page)
    (redisplay-frame-pane (pane-frame layout)
  