anchor.diff:  
   (defvar *balance-after-split-window* t)
   
  +(defun maybe-balance-windows ()
  +  (when *balance-after-split-window*
  +    (balance-windows)))
  +
   (eval-when (:compile-toplevel :load-toplevel)
     (defmacro define-other-window-command (command prompt)
       (if (exist-command-p (string-downcase command))
  
positive.code:              (arg) (,prompt)
             (when (one-window-p)
               (split-window-sensibly (current-window))
               (when *balance-after-split-window*
                 (balance-windows)))
             (other-window)
             (,command arg))
          (warn "command ~a is not defined." command)))
  
negative.code: (define-command other-window-or-split-window (&optional (n 1)) ("p")
    (when (one-window-p)
      (split-window-sensibly (current-window))
      (maybe-balance-windows))
    (other-window n))
  
  (define-command switch-to-last-focused-window () ()
  