title: How to easily Debug Layout Xml Warning/Error?
body: <p>I got stuck on this error:</p>
  
  <pre><code>Warning: simplexml_load_string(): Entity: line 46: parser error : Comment not terminated  in */lib/Varien/Simplexml/Config.php on line 510
  </code></pre>
  
  <p>and</p>
  
  <pre><code>Entity: line 46: parser error : Start tag expected, '&amp;lt;' not found  in */lib/Varien/Simplexml/Config.php on line 510
  </code></pre>
  
  <p>It is clear that there is an issue in some Xml file, but really not easy for me to find out the needle in the big haystack :)</p>
  
  <p>Any good practice for that? 
  If possible I would like to find a good practice that involves use Xdebug, or some log.</p>
  
  <p>It happens a lot of time in Magento to do some miss spelling.</p>