--- a/lisp/auto-show.el	Mon Aug 13 11:19:22 2007 +0200
+++ b/lisp/auto-show.el	Mon Aug 13 11:20:41 2007 +0200
@@ -92,6 +92,17 @@
   :type 'number
   :group 'auto-show)
 
+(defun auto-show-truncationp ()
+  "True if line truncation is enabled for the selected window."
+  ;; XEmacs change (use specifiers)
+  ;; ### There should be a more straightforward way to do this from elisp.
+  (or truncate-lines 
+      (and truncate-partial-width-windows
+	   (< (+ (window-width)
+		 (specifier-instance left-margin-width)
+		 (specifier-instance right-margin-width))
+	      (frame-width)))))
+
 (defun auto-show-mode (arg)
   "Turn automatic horizontal scroll mode on or off.
 With arg, turn auto scrolling on if arg is positive, off otherwise.
@@ -117,7 +128,7 @@
 
 ;; XEmacs addition:
 (defun auto-show-should-take-action-p ()
-  (and auto-show-mode (window-truncated-p)
+  (and auto-show-mode (auto-show-truncationp)
        (equal (window-buffer) (current-buffer))
        (not (memq this-command auto-show-inhibiting-commands))))