.footer should be after .main-content and has the following markup:
Please see the following file for more info: mustache/app/views/layouts/partials/default/footer.mustache
Also if you are using two sidebar elements and the second one which is inside .main-content
is a normal sidebar(i.e. not horizontal), you should move .footer
and put it next to .page-content.
Please see Multiple menu section for more info.