anchor.diff:  
   (defclass window ()
     ((id :accessor id :initarg :id)
  -   (active-buffer :accessor active-buffer)
  +   (active-buffer :accessor active-buffer :initform nil)
      (minibuffer-callbacks :accessor minibuffer-callbacks
                            :initform (make-hash-table :test #'equal))))
   
  
positive.code:   ;;TODO
    )
  
  (defmethod window-set-active-buffer ((interface remote-interface)
                                       (window window)
                                       (buffer buffer))
    (with-slots (host port url) interface
  
negative.code:                               (buffer buffer))
    "Set the active buffer for the active window."
    (let ((window-active (window-active interface)))
      (window-set-active-buffer interface window-active buffer)
      (setf (active-buffer window-active) buffer)))
  