diff --git a/global_filter.widgets.inc b/global_filter.widgets.inc
index f136d94..d59ab2a 100644
--- a/global_filter.widgets.inc
+++ b/global_filter.widgets.inc
@@ -608,7 +608,7 @@ function global_filter_array_flatten($array) {
   foreach ($array as $key => $value) {
     $array[$key] = (array) $value;
   }
-  return call_user_func_array('array_merge', $array);
+  return call_user_func_array('array_merge', array_values($array));
 }