--- a/lisp/prim/scrollbar.el	Mon Aug 13 08:51:05 2007 +0200
+++ b/lisp/prim/scrollbar.el	Mon Aug 13 08:51:32 2007 +0200
@@ -40,8 +40,7 @@
 This is the little arrow to the left of the scrollbar.  One argument is
 passed, the scrollbar's window.  You can advise this function to
 change the scrollbar behavior."
-  (if (not (window-live-p window))
-      nil
+  (when (window-live-p window)
     (scrollbar-set-hscroll window (- (window-hscroll window) 1))
     (setq zmacs-region-stays t)
     nil))
@@ -51,8 +50,7 @@
 This is the little arrow to the right of the scrollbar.  One argument is
 passed, the scrollbar's window.  You can advise this function to
 change the scrollbar behavior."
-  (if (not (window-live-p window))
-      nil
+  (when (window-live-p window)
     (scrollbar-set-hscroll window (+ (window-hscroll window) 1))
     (setq zmacs-region-stays t)
     nil))
@@ -62,8 +60,7 @@
 \(The way this is done can vary from scrollbar to scrollbar.\) One argument is
 passed, the scrollbar's window.  You can advise this function to
 change the scrollbar behavior."
-  (if (not (window-live-p window))
-      nil
+  (when (window-live-p window)
     (scrollbar-set-hscroll window (- (window-hscroll window)
 				     (- (window-width window) 2)))
     (setq zmacs-region-stays t)
@@ -74,8 +71,7 @@
 \(The way this is done can vary from scrollbar to scrollbar.\) One argument is
 passed, the scrollbar's window.  You can advise this function to
 change the scrollbar behavior."
-  (if (not (window-live-p window))
-      nil
+  (when (window-live-p window)
     (scrollbar-set-hscroll window (+ (window-hscroll window)
 				     (- (window-width window) 2)))
     (setq zmacs-region-stays t)
@@ -86,8 +82,7 @@
 \(The way this is done can vary from scrollbar to scrollbar.\). One argument is
 passed, the scrollbar's window.  You can advise this function to
 change the scrollbar behavior."
-  (if (not (window-live-p window))
-      nil
+  (when (window-live-p window)
     (scrollbar-set-hscroll window 0)
     (setq zmacs-region-stays t)
     nil))
@@ -97,8 +92,7 @@
 \(The way this is done can vary from scrollbar to scrollbar.\). One argument is
 passed, the scrollbar's window.  You can advise this function to
 change the scrollbar behavior."
-  (if (not (window-live-p window))
-      nil
+  (when (window-live-p window)
     (scrollbar-set-hscroll window 'max)
     (setq zmacs-region-stays t)
     nil))
@@ -109,9 +103,8 @@
 representing how many columns the thumb is slid over.  You can advise
 this function to change the scrollbar behavior."
   (let ((window (car data))
-	(value (cdr data)))
-    (if (not (or (window-live-p window) (integerp value)))
-	nil
+	(value  (cdr data)))
+    (when (and (window-live-p window) (integerp value))
       (scrollbar-set-hscroll window value)
       (setq zmacs-region-stays t)
       nil)))