When a page with secondary tabs (e.g. $base_url/admin/structure/types/manage/article/display) is rendered in an overlay, and Seven is used as the administrative theme, the secondary tabs for the page are half-hidden under the primary tabs.

I've searched through the CSS but can't find any obvious reason for this. It's really strange since the overlay is in an iframe, and shouldn't be affected by any themeing taking place with Marinelli.