title: indexPathForSelectedRow on previous UITableViews always returns nil?
body: <p>I have a stack of UITableViews managed by a UINavigationController. When I try calling indexPathForSelectedRow on any of the previous UITableViews, I always get nil:</p>
  
  <pre><code>NSEnumerator *e = [[navigationController viewControllers] objectEnumerator];
  UITableViewController *controller;
  while (controller = [e nextObject]) {
      NSIndexPath *selectedIndexPath = [[controller tableView] indexPathForSelectedRow]; // always nil
      // ...
  }</code></pre>
  
  <p>I can't find anything about this behavior in Apple's docs; is it intentional? If so, is there another way to do what I'm trying to do, without me having to resort to manually managing a redundant mySelectedIndexPath instance variable inside didSelectRowAtIndexPath or somesuch?</p>