diff --git a/htdocs/core/class/html.form.class.php b/htdocs/core/class/html.form.class.php
index c89851fe1b7..9a6ae3661dc 100644
--- a/htdocs/core/class/html.form.class.php
+++ b/htdocs/core/class/html.form.class.php
@@ -2462,6 +2462,7 @@ class Form
 	{
 		// phpcs:enable
 		global $langs, $conf;
+		global $hookmanager;
 
 		$out = '';
 		$outarray = array();