diff --git a/phpgwapi/inc/class.html.inc.php b/phpgwapi/inc/class.html.inc.php
index 66bea71957..bdaa126c55 100644
--- a/phpgwapi/inc/class.html.inc.php
+++ b/phpgwapi/inc/class.html.inc.php
@@ -1407,7 +1407,7 @@ class html
 				// actual allowed tags and attributes
 				$config->set('HTML.Allowed', 'br,p[align],b,i,u,s,em,pre,tt,strong,strike,center,div[align],hr[class|style],'.
 							'ul[type],ol[type|start],li,'.
-							'h1,h2,h3,'.
+							'h1,h2,h3,h4,h5,h6,'.
 							'span[class|style],'.
 							'table[class|border|cellpadding|cellspacing|width|style|align|bgcolor|align],'.
 							'tbody,thead,tfoot,colgroup,'.