title: Magento form validation only works on the last checkbox in a group
body: <p>I am using the built-in Magento form validation to ensure the user makes a selection on a particular group of radio boxes.</p>
  
  <p>The code below looks fine however</p>
  
  <pre><code>&lt;div class="input-box"&gt;
    &lt;li class="control"&gt;
     &lt;input type="radio" class="radio organisation_type" value="1" id="billing:organisation_type_1" name="billing[organisation_type]"&gt; &lt;?php echo $this-&gt;__('School') ?&gt;&lt;/li&gt;
    &lt;li class="control"&gt;
     &lt;input type="radio" class="radio organisation_type" value="2" id="billing:organisation_type_2" name="billing[organisation_type]"&gt; &lt;?php echo $this-&gt;__('Parent') ?&gt;&lt;/li&gt;
    &lt;li class="control"&gt;
     &lt;input type="radio" class="radio validate-one-required organisation_type" value="3" id="billing:organisation_type_3" name="billing[organisation_type]"&gt; &lt;?php echo $this-&gt;__('Business') ?&gt;&lt;/li&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>I am using the <em>validate-one</em> method on the class on the last radio box</p>
  
  <p>For some reason the code above will only let me proceed if I select the last radio box?? Can anyone explain why if I check either the first or second box the validation is still failing? </p>