diff --git a/classes/header.php b/classes/header.php
index 6e79960..ad62791 100644
--- a/classes/header.php
+++ b/classes/header.php
@@ -294,7 +294,7 @@ private function get_tabs(course_modinfo $modinfo, \renderer_base $output): \for
                             } while ($parentformatoptions['level'] == 1 && $prevsectionindex >= $firstsection);
 
                             if ($parentformatoptions['firsttabtext']) {
-                                $indextab->content = $parentformatoptions['firsttabtext'];
+                                $indextab->content = format_string($parentformatoptions['firsttabtext'], true, $course->id);
                             } else {
                                 $indextab->content = get_string('index', 'format_onetopic');
                             }