Open link in self tab

[eluser]Unknown[/eluser]
Hi all !. I have a problem with the target tag of anchors. The anchor specification is:

Code:

echo anchor(site_url('areaResponsable/perfil'), "Aquí", array('target' => '_self'));

But, when upload the proyect to the server, the links open in a new tab. And FireBug shows the next anchor:

Code:

<a class="external_link" target="_blank" href="http://apps.manantiales.edu.ar/index.php/areaResponsable/perfil">Aquí</a>

Whats wrong ?. Any idea ?.