anchor.diff:  (defun make-window (buffer nlines ncols y x)
     (let ((window
            (make-instance 'window
  -          :win (cl-ncurses:newwin nlines ncols y x)
  -          :nlines nlines
  -          :ncols ncols
  -          :y y
  -          :x x
  -          :buffer buffer
  -          :vtop-linum 1
  -          :cur-linum 1
  -          :cur-col 0
  -          :max-col 0)))
  +                        :win (cl-ncurses:newwin nlines ncols y x)
  +                        :nlines nlines
  +                        :ncols ncols
  +                        :y y
  +                        :x x
  +                        :buffer buffer
  +                        :display-lines (make-array nlines :initial-element "")
  +                        :vtop-linum 1
  +                        :cur-linum 1
  +                        :cur-col 0
  +                        :max-col 0)))
       window))
   
   (defvar *current-cols*)
  
positive.code: 
  (define-key *global-keymap* "C-l" 'recenter)
  (define-command recenter () ()
    (window-recenter *current-window*))
  
  (defun window-recenter (window)
    (setf (window-vtop-linum window)
  
negative.code: (defun window-set-size (window nlines ncols)
    (cl-ncurses:wresize (window-win window) nlines ncols)
    (setf (window-nlines window) nlines)
    (setf (window-ncols window) ncols)
    (setf (window-display-lines window)
          (make-array nlines :initial-element "")))
  
  (defun window-move (window dy dx)
    (window-set-pos window
  