Allows to add tabs to the Preview Customer page in the Administration Area.
The event handler should accept two parameters - the controller object and the customer object.
The handler should return an associative array of tab titles and corresponding tab partials.
public function subscribeEvents()
{
Backend::$events->addEvent('shop:onExtendCustomerPreviewTabs', $this, 'add_customer_preview_tabs');
}
public function add_customer_preview_tabs($controller, $customer)
{
return array('Special information'=>PATH_APP.'/mymodule/partials/special.htm');
}