diff --git a/mod/assign/locallib.php b/mod/assign/locallib.php
index a6dd9bc1fed..48375937769 100644
--- a/mod/assign/locallib.php
+++ b/mod/assign/locallib.php
@@ -3966,7 +3966,9 @@ class assign {
         if (!$last) {
             $buttonarray[] = $mform->createElement('submit', 'nosaveandnext', get_string('nosavebutnext', 'assign'));
         }
-        $mform->addGroup($buttonarray, 'navar', '', array(' '), false);
+        if (!empty($buttonarray)) {
+            $mform->addGroup($buttonarray, 'navar', '', array(' '), false);
+        }
     }