anchor.diff:    (delete-point (%window-point window))
     (screen-delete (window-screen window)))
   
  -(defun window-topleft-y () (length (header-windows)))
  +(defun window-topleft-y () (length (frame-header-windows (get-impl-frame))))
   (defun window-topleft-x () 0)
   (defun window-max-width () (- (display-width) (window-topleft-x)))
   (defun window-max-height ()
  
positive.code: (defvar *use-new-vertical-move-function* t)
  (defvar *use-cursor-movement-workaround* t)
  
  (defun floating-windows (&optional (frame (first *frame-list*)))
    (frame-floating-windows frame))
  (defun (setf floating-windows) (new-floating-windows)
    (let ((frame (first *frame-list*)))  ;; TODO: to parametrize
      (setf (frame-floating-windows frame) new-floating-windows)))
  
  (defun header-windows (&optional (frame (first *frame-list*)))
    (frame-header-windows frame))
  (defun (setf header-windows) (new-header-windows)
    (let ((frame (first *frame-list*)))  ;; TODO: to parametrize
      (setf (frame-header-windows frame) new-header-windows)))
  
  (defun modified-floating-windows (&optional (frame (first *frame-list*)))
    (frame-modified-floating-windows frame))
  (defun (setf modified-floating-windows) (new-modified-floating-windows)
    (let ((frame (first *frame-list*)))  ;; TODO: to parametrize
      (setf (frame-modified-floating-windows frame) new-modified-floating-windows)))
  
  (defun modified-header-windows (&optional (frame (first *frame-list*)))
    (frame-modified-header-windows frame))
  (defun (setf modified-header-windows) (new-modified-header-windows)
    (let ((frame (first *frame-list*)))  ;; TODO: to parametrize
      (setf (frame-modified-header-windows frame) new-modified-header-windows)))
  
  (defclass window ()
    ((id
      :initform (mod (incf *window-id-counter*) most-positive-fixnum)
  
negative.code: (defun (setf window-parameter) (value window parameter)
    (setf (getf (window-parameters window) parameter) value))
  
  (defun current-window ()
    (frame-current-window (get-impl-frame)))
  
  (defun (setf current-window) (new-window)
    (let ((frame (get-impl-frame)))
      (check-type new-window window)
      (when (frame-current-window frame)
        (let ((old-window (current-window)))
  