I am trying to insert a new admin tab before Root.Content.Main without any luck. I've tried:
$fields->insertBefore(new Tab('Root.Content.Overview', 'Overview'), 'Root.Content.Main');
and
$fields->addFieldToTab('Root.Content', new Tab('OverviewTab', 'Root.Content.Overview'), 'Root.Content.Main');
without any luck.
Anyone have any ideas? I've hunted through the API but there isn't much explanation as to how the tab naming system works.