title: JQuery Dialog('open') not working
body: <p>Here is a sample <a href="http://jsfiddle.net/mUpjw/15/" rel="noreferrer">http://jsfiddle.net/mUpjw/15/</a></p>
  
  <p>I had JQuery 1.2 in some old code and it was opening dialog this way.</p>
  
  <pre><code>$('#myDiv').dialog('open');
  </code></pre>
  
  <p>I upgraded to jquery 1.6.1 and it was working fine . But if I add a DOCTYPE than it doesnt work but if I do </p>
  
  <pre><code>$('#myDiv').dialog();
  </code></pre>
  
  <p>That works fine.</p>
  
  <p>What can be reason for this ?</p>