--- a/jdk/src/share/classes/sun/awt/SunToolkit.java	Sun Jul 12 23:20:26 2009 -0700
+++ b/jdk/src/share/classes/sun/awt/SunToolkit.java	Tue Jul 14 14:08:47 2009 +0400
@@ -1985,8 +1985,7 @@
      */
     public static boolean isContainingTopLevelOpaque(Component c) {
         Window w = getContainingWindow(c);
-        return w != null && ((Window)w).getBackground() != null &&
-            ((Window)w).getBackground().getAlpha() == 255;
+        return w != null && w.isOpaque();
     }
 
     /**