anchor.diff:                 (window-tree-parent (window-node-cdr tree) node))))))
   
   (defun window-list (&optional (frame (current-frame)))
  -  (window-tree-flatten
  -   (frame-window-tree frame)))
  +  (window-tree-flatten (frame-window-tree frame)))
   
   (defun one-window-p ()
     (window-tree-leaf-p (window-tree)))
  
positive.code:     (setf (frame-window-tree frame) window)))
  
  (defun teardown-windows (frame)
    (mapc #'%free-window (window-list frame)))
  
  (defun window-recenter (window)
    (line-start
  
negative.code:                  :use-modeline-p use-modeline-p))
  
  (defun clear-screens-of-window-list ()
    (flet ((clear-screen (window)
             (screen-clear (window-screen window))))
      (mapc #'clear-screen (window-list))
      (mapc #'clear-screen (frame-floating-windows (current-frame)))))
  
  (defgeneric %delete-window (window))
  (defgeneric window-redraw (window force)
  