MENU_DEFAULT_LOCAL_TASK

Every set of local tasks should provide one "default" task, that links to the same path as its parent when clicked.

5/includes/menu.inc, line 140

<?php
define('MENU_DEFAULT_LOCAL_TASK', MENU_IS_LOCAL_TASK | MENU_LINKS_TO_PARENT);
?>

Related topics

Menu system
Define the navigation menus, and route page requests to code based on URLs.