title: jQuery Dialog theme not being applied
body: <p>I'm using jquery-1.4.2.min.js and jquery-ui-1.8.1.custom.min.js.  According to Firebug, both minimized scripts have been loaded. They both appear in the dropdown list on Firebug's Scripts tab.</p>
  
  <p>The dialog is launching, but there's no background and so the text below it shows through, and there's no "window" stuff at all, no titlebar, no X button.  Just the floating/draggable text with a -close- link at the top left corner.</p>
  
  <p>I was under the impression from reading these pages</p>
  
  <pre><code> http://jqueryui.com/demos/dialog/
   http://jqueryui.com/themeroller/
  </code></pre>
  
  <p>that the UI theme-driven appearance would be automatically applied to the dialog when it was invoked using this barebones call:</p>
  
  <pre><code> $('#dialog').dialog()
  </code></pre>
  
  <p>I would be grateful for suggestions on how to troubleshoot this. Thanks</p>