title: cakephp populate HABTM select box in EDIT form
body: <p>I am using cakephp's form for an HABTM relationship between User and Event.  There is a join table events_users.  The form works well for the Add form, but not for the edit form.  The code is:</p>
  
  <p>Controller:</p>
  
  <pre><code>$this-&gt;data = $this-&gt;Event-&gt;findById($id);
  </code></pre>
  
  <p>Form field:</p>
  
  <pre><code>$this-&gt;Form-&gt;input('User');
  </code></pre>
  
  <p>What I get is a blank, input box.  Unlike the select box in the Add form.  Any ideas what I'm doing wrong or how to populate a select box with the right Users selected for the input on the edit form?</p>