--- bbp-admin/bbp-metaboxes.php	Mon May 09 11:35:08 2011
+++ bbp-admin/bbp-metaboxes.php	Mon May 09 11:35:34 2011
@@ -393,8 +393,7 @@
 		'post_type'   => bbp_get_topic_post_type(),
 		'selected'    => $post->post_parent,
 		'select_id'   => 'parent_id',
-		'orderby'     => 'post_date',
-		'numberposts' => '50'
+		'orderby'     => 'post_date'
 	); ?>
 
 	<p><strong><?php _e( 'Parent Topic', 'bbpress' ); ?></strong></p>