Why does this jQuery return an index of 3?
<p>HTML:</p>

<pre><code>&lt;ul&gt;
    &lt;li class="selected"&gt;First Item&lt;/li&gt;
    &lt;li class="disabled"&gt;Second Item&lt;/li&gt;
    &lt;li class="separator"&gt;Third Item&lt;/li&gt;
    &lt;li&gt;Fourth Item&lt;/li&gt;
&lt;/ul&gt;
</code></pre>

<p>jQuery:</p>

<pre><code>alert($("li:not(.disabled,.separator)").index());
</code></pre>

<p>According to <a href="http://api.jquery.com/index/">the documentation</a> for index:</p>

<blockquote>
  <p>the return value is an integer indicating the position of the first
  element within the jQuery object relative to its sibling elements.</p>
</blockquote>

<p>Emphasis on <code>first element</code>.  But the above code returns <code>3</code>.  Based on the documentation shouldn't this code return <code>0</code>?</p>

<p>You can see it in action here: <a href="http://jsfiddle.net/Zf9Vv/">http://jsfiddle.net/Zf9Vv/</a></p>

<p><strong>NOTE:</strong></p>

<p>My selector matches two elements: the first and last <code>LI</code>.</p>
