title: XPath parent axis not behaving as expected
body: <p>Given the following XML document:</p>
  <pre><code>&lt;table&gt;
  &lt;tr&gt;   &lt;td&gt;A&lt;/td&gt;         &lt;td&gt;B&lt;/td&gt;         &lt;td&gt;C&lt;/td&gt;     &lt;/tr&gt;
  &lt;tr&gt;   &lt;td&gt;D&lt;/td&gt;       &lt;td&gt;E&lt;/td&gt;    &lt;td&gt;E&lt;/td&gt;      &lt;/tr&gt;
  &lt;tr&gt;   &lt;td&gt;F&lt;/td&gt;    &lt;td&gt;G&lt;/td&gt;         &lt;td&gt;H&lt;/td&gt;      &lt;/tr&gt;
  &lt;/table&gt;
  </code></pre>
  <p>I get different results for the following expressions and I don't understand what is the reason for that.</p>
  <p>for: <code>//td[parent::td]</code> I get an empty set (namely, &quot;No match&quot;).<br />
  for: <code>//td[..]</code> I get list of all the <code>td</code> elements.</p>
  <p>I don't understand what is the difference between the expressions, because that <code>..</code> is shortcut of <code>parent::</code>.</p>