anchor.diff:  
   (defclass minibuffer (buffer)
     ((default-modes :initform '(minibuffer-mode))
  -   (completion-function :accessor completion-function)
  +   (completion-function :accessor completion-function :initform nil)
      (callback-function :accessor callback-function)
      (callback-buffer :accessor callback-buffer
                       :documentation "The active buffer when the minibuffer was
  
positive.code:           (setf (display-mode minibuffer) :echo)
            (erase-document minibuffer)
            (rpc-window-set-minibuffer-height *interface*
                                            window
                                            (minibuffer-echo-height window))
            (let ((style (cl-css:css
                          '((* :font-family "monospace,monospace"
                               :font-size "14px")
  
negative.code:   (let ((active-window (rpc-window-active interface)))
      (setf (minibuffer-active active-window) t)
      (rpc-window-set-minibuffer-height interface
                                        active-window
                                        (minibuffer-open-height active-window))))
  
  (defmethod hide ((interface remote-interface))
    (let ((active-window (rpc-window-active interface)))
  