title: dequeueReusableHeaderFooterViewWithIdentifier is returning nil for cell, but dequeueReusableCellWithIdentifier isn't
body: <p>I'm adding a footer to a table view using a prototype cell in Interface Builder:</p>
  
  <p><a href="https://i.stack.imgur.com/KlhZK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KlhZK.png" alt="enter image description here"></a></p>
  
  <p>When instantiating the footer, <code>dequeueReusableHeaderFooterViewWithIdentifier()</code> is returning nil for cell, but <code>dequeueReusableCellWithIdentifier()</code> isn't. I've created a footer view with the correct identifier in Interface Builder:</p>
  
  <p><img src="https://i.stack.imgur.com/KLSGE.png" width="280"></p>
  
  <p>And then I instantiate the footer:</p>
  
  <pre><code>func tableView(tableView: UITableView, viewForFooterInSection section: Int) -&gt; UIView? {
      let id = "MyFooter"
  //    this works:
  //    guard let footerCell = self.todaysChoresTableView.dequeueReusableCellWithIdentifier(id) else { 
  //        return nil 
  //    }
      guard let footerCell = self.todaysChoresTableView.dequeueReusableHeaderFooterViewWithIdentifier(id) else {
          // this doesn't, always returning nil
          return nil
      }
  }
  </code></pre>
  
  <p>Why is <code>dequeueReusableHeaderFooterViewWithIdentifier()</code> always returning nil?</p>
  
  <pre><code>(lldb) po self.tableView.dequeueReusableHeaderFooterViewWithIdentifier(id)
  nil
  
  (lldb) po self.tableView.dequeueReusableCellWithIdentifier(id)
  ▿ Optional(&lt;UITableViewCell: 0x7fa313c835f0; frame = (0 0; 600 44); clipsToBounds = YES; layer = &lt;CALayer: 0x7fa313c73150&gt;&gt;)
    - Some : &lt;UITableViewCell: 0x7fa313c835f0; frame = (0 0; 600 44); clipsToBounds = YES; layer = &lt;CALayer: 0x7fa313c73150→
  </code></pre>
  
  <h3>Update:</h3>
  
  <p>I've tried doing this too, and while now it isn't <code>nil</code> anymore, it doesn't seem to actually build a view based on my IB design:</p>
  
  <pre><code>tableView.registerClass(UITableViewHeaderFooterView.self, forHeaderFooterViewReuseIdentifier: id)
  let footerView: UITableViewHeaderFooterView? = self.todaysChoresTableView.dequeueReusableHeaderFooterViewWithIdentifier(id)
  footerView!.backgroundColor = UIColor.redColor()
  return footerView
  </code></pre>