diff --git a/main/inc/lib/pear/HTML/QuickForm.php b/main/inc/lib/pear/HTML/QuickForm.php
index 80f3e90d03..8d990fbc89 100644
--- a/main/inc/lib/pear/HTML/QuickForm.php
+++ b/main/inc/lib/pear/HTML/QuickForm.php
@@ -1334,7 +1334,7 @@ class HTML_QuickForm extends HTML_Common
     * @param    array   $b  array which will be merged into first one
     * @return   array   merged array
     */
-    function arrayMerge($a, $b)
+    static function arrayMerge($a, $b)
     {
         foreach ($b as $k => $v) {
             if (is_array($v)) {