title: delete button not showing in uitableview
body: <p>I've added UITableView to a UIViewController. This ViewController is pushed to a navigationcontroller stack.</p>
  
  <p>I've got an edit button in the tool bar but the delete buttons are not showing up in the cells.</p>
  
  <p>When I hit edit, the edit button switched to a "done" state.</p>
  
  <p>The following tableview method is entered. What would be a likely cause for the delete buttons not showing up?</p>
  
  <pre><code>- (void)setEditing:(BOOL)editing animated:(BOOL)animated {
  
      // Prevent new objects being added when in editing mode.
      [super setEditing:(BOOL)editing animated:(BOOL)animated];
      self.navigationController.navigationItem.rightBarButtonItem.enabled = !editing;
  }
  </code></pre>