Please put pseudo elements (:before, :after) in the Inspector DOM list as Chrome does. As it stands I have no way to inspect the computed styles of a pseudo element.
You can currently see the pseudo element styles (like :before and :after) if you select the element in the DOM Tree which has :before/:after pseudo elements. Duping to a bug that covers putting pseudo elements into the DOM Tree itself. *** This bug has been marked as a duplicate of bug 139612 ***
You are correct about "Computed Styles" though. Right now you can only see the Rules for pseudo elements.