title: HABTM dropdown items not selected
body: <p>I created a site for fun to learn CakePHP but for some reason I can't get a multiple select dropdown box to show my selected items. In this example 1 video game can have multiple difficulties (easy, normal, hard). On my Game edit page I have a multi select box to pick the difficulties. It shows all three difficulties and I can select them and it saves correctly. However when I return to the edit page the items I previously saved do not show highlighted as selected. I have verified that the records are saving correctly in the database.</p>
  
  <p>Tables:
  games
  difficulties
  difficulties_games</p>
  
  <p>Models:</p>
  
  <pre><code>class Game extends AppModel {
  public $actsAs = array('Containable');
  public $hasAndBelongsToMany = array(
      'Difficulty' =&gt;
          array(
              'className' =&gt; 'Difficulty',
              'joinTable' =&gt; 'difficulties_games',
              'foreignKey' =&gt; 'game_id',
              'associationForeignKey' =&gt; 'difficulty_id',
              'unique' =&gt; 'true'
              )
  );
  }
  class Difficulty extends AppModel {
  public $actsAs = array('Containable');
  public $hasAndBelongsToMany = array(
      'Game' =&gt;
          array(
              'className' =&gt; 'Game',
              'joinTable' =&gt; 'difficulties_games',
              'foreignKey' =&gt; 'difficulty_id',
              'associationForeignKey' =&gt; 'game_id',
              'unique' =&gt; 'true'
              )
  );
  }
  </code></pre>
  
  <p>Controller:</p>
  
  <pre><code>$game = $this-&gt;Game-&gt;findById($id);
  $this-&gt;set('difficulties', $this-&gt;Game-&gt;Difficulty-&gt;find('list'));
  </code></pre>
  
  <p>View (edit.ctp):</p>
  
  <pre><code>echo $this-&gt;Form-&gt;input('Difficulty');
  </code></pre>
  
  <p>This has to be something simple I am missing but I've read through the book on HABTM and searched here and couldn't find much on multi-select boxes. </p>
  
  <p>UPDATE:</p>
  
  <p>Here is the entire edit function in the controller:</p>
  
  <pre><code>public function edit($id = null) {
      if (!$id) {
          throw new NotFoundException(__('Invalid post'));
      }
  
      $game = $this-&gt;Game-&gt;findById($id);
      if (!$game) {
          throw new NotFoundException(__('Invalid post'));
      }
      if ($this-&gt;request-&gt;is('post') || $this-&gt;request-&gt;is('put')) {
          $this-&gt;Game-&gt;id = $id;
          if ($this-&gt;Game-&gt;saveAll($this-&gt;request-&gt;data)) {
              $this-&gt;Session-&gt;setFlash('Your game has been updated.');
              $this-&gt;redirect(array('action' =&gt; 'index'));
          } else {
              $this-&gt;Session-&gt;setFlash($this-&gt;Game-&gt;invalidFields());
          }
      }
  
      if (!$this-&gt;request-&gt;data) {
          $this-&gt;request-&gt;data = $game;
      }
      $this-&gt;set('systems', $this-&gt;Game-&gt;System-&gt;find('list'));
      $this-&gt;set('genres', $this-&gt;Game-&gt;Genre-&gt;find('list'));
      $this-&gt;set('difficulties', $this-&gt;Game-&gt;Difficulty-&gt;find('list'));
  
  
  }
  </code></pre>
  
  <p>Also here is some more on the View:</p>
  
  <pre><code>echo $this-&gt;Form-&gt;create('Game');
  echo $this-&gt;Form-&gt;input('name');
  echo $this-&gt;Form-&gt;input('system_id');
  echo $this-&gt;Form-&gt;input('genre_id');
  echo $this-&gt;Form-&gt;input('Difficulty');
  echo $this-&gt;Form-&gt;input('id', array('type' =&gt; 'hidden'));
  echo $this-&gt;Form-&gt;end('Save Game');
  </code></pre>