diff --git a/term_reference_tree.widget.inc b/term_reference_tree.widget.inc
index ae96baa..5f9f974 100644
--- a/term_reference_tree.widget.inc
+++ b/term_reference_tree.widget.inc
@@ -539,6 +539,7 @@ function _term_reference_tree_widget_validate(&$element, &$form_state) {
   }
 
   if ($element['#required'] && count($value) == 0) {
+    // The title is already check_plained so it's appropriate to use !.
     form_error($element, t('!name field is required.', array('!name' => $element['#title'])));
   }