anchor.diff:                  (+ (window-x window) 1))
           (push window delete-windows)))
       (mapc #'delete-window delete-windows))
  -  (let ((window-list (window-tree-flatten *window-tree*)))
  +  (let ((window-list (window-tree-flatten (window-tree))))
       (dolist (window (collect-right-windows window-list))
         (window-resize window
                        0
  
positive.code:     (setf (window-current-charpos new-window)
            (window-current-charpos current-window))
      (multiple-value-bind (node getter setter)
          (window-tree-parent *window-tree* current-window)
        (if (null node)
            (setq *window-tree*
                  (make-window-node split-type
                                    current-window
                                    new-window))
  
negative.code:                         setter
                          another-getter
                          another-setter)
        (window-tree-parent (window-tree) node)
      (declare (ignore setter another-setter))
      (cond ((null parent-node) nil)
            ((eq split-type (window-node-split-type parent-node))
  