anchor.diff:  
   (define-command cancel-input (minibuffer-mode &optional (minibuffer (minibuffer *interface*)))
     "Close the minibuffer query without further action."
  -  (log:debug (callback-buffer minibuffer))
     (setf (display-mode minibuffer) :nil)
  -  (set-active-buffer *interface* (callback-buffer minibuffer))
     (with-slots (cleanup-function) minibuffer
       (when cleanup-function
         (funcall cleanup-function)))
  
positive.code:   "Return with minibuffer selection."
    (hide *interface*)
    (setf (display-mode minibuffer) :nil)
    (set-active-buffer *interface* (callback-buffer minibuffer))
    (with-slots (callback-function cleanup-function
                 empty-complete-immediate completions completion-cursor)
        minibuffer
  
negative.code:   ((default-modes :initform '(minibuffer-mode))
     (completion-function :accessor completion-function)
     (callback-function :accessor callback-function)
     (callback-buffer :accessor callback-buffer
                      :documentation "The active buffer when the minibuffer was
  brought up.  This can be useful to know which was the original buffer in the
  `callback-function' in case the buffer was changed.")
     (setup-function :accessor setup-function)
     (cleanup-function :accessor cleanup-function)
     (empty-complete-immediate :accessor empty-complete-immediate)
  