diff --git a/ext/session/session.c b/ext/session/session.c
index be86dcae7fe..fb7d29d050d 100644
--- a/ext/session/session.c
+++ b/ext/session/session.c
@@ -1498,6 +1498,10 @@ PHPAPI void php_session_reset_id(void) /* {{{ */
 	}
 
 	if (APPLY_TRANS_SID) {
+		/* FIXME: Restting vars are required when
+		   session is stop/start/regenerated. However,
+		   php_url_scanner_reset_vars() resets all vars
+		   including other URL rewrites set by elsewhere. */
 		/* php_url_scanner_reset_vars(); */
 		php_url_scanner_add_var(PS(session_name), strlen(PS(session_name)), ZSTR_VAL(PS(id)), ZSTR_LEN(PS(id)), 1);
 	}