title: Select2 not calculating `resolved` width correctly if select is hidden
body: <p>I am using Twitter bootstrap and <a href="http://ivaynberg.github.com/select2/" rel="noreferrer">the fantastic Select2 plugin</a>.</p>
  
  <p>These are working great, I realized you need to set <code>{width: 'resolve'}</code> when initiating Select2 otherwise it looks messed up!.</p>
  
  <p>But I am having an issue with one of my selects, as you can see in the image below, the <code>Referee Type</code> select has an incorrect width.</p>
  
  <p>This is caused due to this field being initially hidden, and only becoming visible if <em>Referee</em> is selected in the <em>Group</em> field.</p>
  
  <p>So, how can I fix this?</p>
  
  <p><img src="https://i.stack.imgur.com/Ma2Vz.png" alt="Inputs"></p>