anchor.diff:            (abort-gesture ()
               (display-message "Aborted")))
           (display-drei drei)
  -        (when (modified-p (buffer drei))
  +        (when (and (modified-p (buffer drei))
  +                   (gadget-value-changed-callback drei))
             (clear-modify (buffer drei))
             (value-changed-callback drei
                                     (gadget-client drei)
  
positive.code:   (activate-gadget drei))
  
  (defmethod gadget-value ((gadget drei-gadget-pane))
    (buffer-substring (buffer gadget)
                      0 (size (buffer gadget))))
  
  (defmethod (setf gadget-value) (new-value (gadget drei-gadget-pane)
                                  &key (invoke-callback t))
  
negative.code:   (check-type initial-contents array)
    (check-type border-width integer)
    (check-type scroll-bars (member t :both :vertical :horizontal nil))
    (with-keywords-removed (args (:minibuffer :scroll-bars :border-width
                                              :syntax :drei-class))
      (let* ((borderp (and border-width (plusp border-width)))
             (minibuffer-pane (cond ((eq minibuffer t)
                                     (make-pane 'drei-minibuffer-pane))
  