anchor.diff:                     :called-window (prompt-window-called-window parameters)
                      :history (prompt-window-history parameters))))
   
  -(defmethod lem::update-prompt-window ((window prompt-window))
  +(defmethod lem::update-prompt-window ((window floating-prompt-window))
     (destructuring-bind (x y width height)
         (compute-window-rectangle (window-buffer window))
       (unless (and (= x (window-x window))
  
positive.code:     :initform nil
      :reader prompt-window-history)))
  
  (defclass prompt-window (floating-window prompt-parameters)
    ((start-point
      :accessor prompt-window-start-charpos))
    (:default-initargs
  
negative.code: (defun make-prompt-window (buffer parameters)
    (destructuring-bind (x y width height)
        (compute-window-rectangle buffer)
      (make-instance 'floating-prompt-window
                     :buffer buffer
                     :x x
                     :y y
  