Why does the HTML editor in the CMS editor kick out some of the HTML?

[matt.wiw]

Prestashop Version 1.1.0.5

I am in the backoffice cms trying to create a custom page using the html mode:

I have simply added rel="" tags and it kicks them when I click "update."

Why does it do that? Is there any way to override the auto formatting? Why doesn't the html edit mode actually mean html edit mode?

Thanks for any help.