Index: wp-includes/class-wp-customize-manager.php
===================================================================
--- wp-includes/class-wp-customize-manager.php	(revision 20854)
+++ wp-includes/class-wp-customize-manager.php	(working copy)
@@ -483,7 +483,7 @@
 		$bp = $b->priority;
 
 		if ( $ap == $bp )
-			return 0;
+			return strcmp( $a->id, $b->id );
 		return ( $ap > $bp ) ? 1 : -1;
 	}