anchor.diff:            window-buffer
             window-view
             window-parameter
  +          window-delete-hook
             window-redraw
             current-window
             window-list
  
positive.code: 
  (defun delete-window (window)
    (%delete-window window)
    (when (window-delete-hook window)
      (funcall (window-delete-hook window)))
    (%free-window window)
    t)
  
  
negative.code:     :type point)
     (delete-hook
      :initform nil
      :accessor window-delete-hook)
     (use-modeline-p
      :initarg :use-modeline-p
      :initform nil
  