It's not correct.
Submenu items (e.g Blog -> Blog post) has correct link while the parent item (Blog) that by default don't have link, get the link of last visited view (http://localhost/Admin/Customer/List).
My version is 2.65.
if (!string.IsNullOrWhiteSpace(item.ControllerName) &&
!string.IsNullOrWhiteSpace(item.ActionName))
{
item.RouteValues = new RouteValueDictionary() { { "area", "Admin" } };
}