title: Jquery-ui dialog box 'x' button image is not visible
body: <p>I am doing a simple jquery-ui dialog application with my js,css code as,</p>
  
  <pre><code>&lt;html&gt;
    &lt;head&gt;
      &lt;link rel="stylesheet" type="text/css" href="jquery-ui.css"&gt;
    &lt;/head&gt;
    &lt;body&gt;
      &lt;div id="dialog"&gt;this is a dialog box&lt;/div&gt;
      &lt;script src="jquery.js"&gt;&lt;/script&gt;
      &lt;script src="jquery-ui.js"&gt;&lt;/script&gt;
      this jquery ui is added.....
      &lt;script&gt;     
        $("#dialog").dialog() 
      &lt;/script&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>When i add a simple dialog box, the <code>x</code> mark inside the dialog's close button is not visible. </p>
  
  <p>Am i missing inclusion of any image sprite file?<img src="https://i.stack.imgur.com/xm2bZ.png" alt="enter image description here"></p>