title: Update panel can not find the button which trigger it
body: <p>I have a button is inside a another table(s) inside the update panel. </p>
  
  <pre><code>&lt;Update panel&gt;
  &lt;ContentTemplate&gt;
  &lt;table&gt;
    &lt;table&gt;
      &lt;Button&gt;
   &lt;table&gt;
  &lt;table&gt;
  &lt;/ContentTemplate&gt;
  &lt;/Update panel&gt;
  </code></pre>
  
  <p>I would like to add a button to Update panel's trigger. 
  But am getting an err says "Update panel can not find the button which trigger it".</p>
  
  <p>I am getting "Sys.Webforms.PageRequestmanagerParseErrorException: This message recieved from manager could not be parsed. Common cause for this error are when response is modified by response.write"</p>
  
  <p>Please help!</p>