title: Tabbing does not work in a chrome extension
body: <p>I am trying to build a simple login form in a chrome extension. In my popup.html, I have a few input fields that have their corresponding tabindex values set. The username field has the autofocus property set through HTML or <code>$('#myelement').focus()</code> (I've tried both methods). </p>
  
  <p>For some reason, tabbing does not work on my form when I first click the button next to the omnibar to open the popup. The username field has focus, but pressing the tab key makes the cursor disappear. It only shows up again if I explicitly click one of the input fields and then tab over, but never when they popup first opens. </p>
  
  <pre><code>&lt;input type="text" id="one" tabindex=1 autofocus /&gt;
  &lt;input type="text" id="two" tabindex=2 /&gt;
  </code></pre>
  
  <p>If I open popup.html in a web browser (and not the extension), I've noticed that the tabbing in my form works perfectly. </p>