Index: wp-includes/shortcodes.php
===================================================================
--- wp-includes/shortcodes.php	(revision 26383)
+++ wp-includes/shortcodes.php	(working copy)
@@ -159,6 +159,9 @@
 		foreach ( $matches as $shortcode ) {
 			if ( $tag === $shortcode[2] )
 				return true;
+			// Run recursively on the content of the shortcode.
+			elseif ( has_shortcode( $shortcode[5], $tag) )
+				return true
 		}
 	}
 	return false;