Can't go to front page by clicking logo or menu when admin

Strange goings on - When I click the logo, I would expect to go to the front page. However, when logged in as admin (haven't tried other roles, but it works for anonymous), the link created on the logo is current page+overlay - for instance
http://mysite.mydomain.com/content/om-os#overlay=
instead of
http://mysite.mydomain.com
Page.tpl says the standard
<div id="site-name"><a href="<?php print check_url($front_page); ?>" title="<?php print t('Home'); ?>" rel="home"><?php print $site_name; ?></a></div>
Anybody experienced that?
At first I thougt the recently installed Administration Menu was the culprit - but I've just disabled that and cleared cache, and ti still acts up.