In SugarCRM, global links ( such as Employees, Admin, Support, About) are defined in /include/globalControlLinks.php file. Those links appear in top right corner of the screen, usualy after “Welcome, Administrator [Log Out]” message.
If you have to modify, remove or add some new links there is an upgrade safe method to do that in /custom folder.
You just have to create a file, if not exists, at location /custom/include/globalControlLinks.php.
To remove, for example, the “Support” link you must add the following line of code:
unset($global_control_links['training']);
To add some new link you have to write somethink like:
$global_control_links['dobre_link'] = array('linkinfo' => array('Dobre.name'=>'http://www.dobre.name/'));
You can also write this code in an upgrade safe manner in /custom/application/Ext/GlobalLinks/links.ext.php
You must remember that last one has priority in front of /custom/include/globalControlLinks.php, that has priority in front of /include/globalControlLinks.php 