--- a/.emacs-my	Tue Feb 22 00:40:24 2011 +0200
+++ b/.emacs-my	Tue Feb 22 20:20:55 2011 +0200
@@ -126,7 +126,7 @@
   (when (>= emacs-major-version 22) (tooltip-mode -1))
   )
 
-(when window-system
+(when (and window-system (>= emacs-major-version 23))
   ;; Prefer horizontal windows splitting.
   (setq split-height-threshold nil)
   (setq split-width-threshold nil)