Missing target="_parent", external URL menu type

When creating a menu item type 'External URL', with target window "parent", it is missing the target="_parent" to get link opens in parent frame.

Note: "_parent" needed in firefox when site in a pinned tab.

Issue Tracker 33327 : http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=33327