static void
set_api_state(api_data *api)
{
   const Eina_List *items = elm_box_children_get(api->box);
   if (!eina_list_count(items))
     return;

   /* Get first item of list of vbox children */
   Evas_Object *fs_bt = eina_list_nth(items, 0);

   /* use elm_box_children_get() to get list of children */
   switch(api->state)
     { /* Put all api-changes under switch */
      case ICON_UNSET:
         elm_object_part_content_unset(fs_bt, NULL);
         break;

      case WINDOW_TITLE_SET:
         elm_fileselector_button_window_title_set(fs_bt, "Custom title from API");
         break;

      case API_STATE_LAST:

         break;
      default:
         return;
     }
}
PREFIX value ml_elm_fileselector_button_window_title_set(
        value v_obj, value v_title)
{
        elm_fileselector_button_window_title_set(Evas_Object_val(v_obj),
                String_val(v_title));
        return Val_unit;
}