anchor.diff:  
   (defclass debugger-pane (application-pane)
     ((condition-info :reader  condition-info :initarg :condition-info)
  +   (active-frame :accessor active-frame :initform 0)
      (shown-frames :accessor shown-frames :initform 5)))
   
   (defun make-debugger-pane ()
  
positive.code: 
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;   Commands   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  
  
negative.code: (define-clim-debugger-command (com-refresh :name "Refresh" :menu t
  					   :keystroke #\r) ()
    (change-space-requirements (frame-panes *application-frame*)))
  (define-clim-debugger-command (com-next :keystroke :next)
      ()
    (let ((pane (clim:find-pane-named *application-frame* 'debugger-pane)))
      (incf (active-frame pane))
      (when (= (active-frame pane) (shown-frames pane))
        (com-more))
      (when (= (active-frame pane) (shown-frames pane))
        (decf (active-frame pane)))))
  
  (define-clim-debugger-command (com-prev :keystroke :prev)
      ()
    (let ((pane (clim:find-pane-named *application-frame* 'debugger-pane)))
      (setf #1=(active-frame pane) (max (1- #1#) 0))))
  
  (define-clim-debugger-command (com-quit :name "Quit" :menu t
  					:keystroke :exit) ()
    (frame-exit *application-frame*))
  
  (define-clim-debugger-command (com-invoke-restart :name "Invoke restart")
  