diff --git a/htdocs/core/lib/ajax.lib.php b/htdocs/core/lib/ajax.lib.php
index 72592b1e68f..cddd5cc557e 100644
--- a/htdocs/core/lib/ajax.lib.php
+++ b/htdocs/core/lib/ajax.lib.php
@@ -272,7 +272,7 @@ function ajax_dialog($title,$message,$w=350,$h=150)
 {
 	global $langs;
 
-	$msg.= '<div id="dialog-info" title="'.dol_escape_htmltag($title).'">';
+	$msg= '<div id="dialog-info" title="'.dol_escape_htmltag($title).'">';
 	$msg.= $message;
 	$msg.= '</div>'."\n";
     $msg.= '<script type="text/javascript">