TBODY tag in a XHTML table

For all HTML language lawyers out there... I've got a page that is defined as XHTML 1.0 Transitional and in it I use a table that has many <tbody> tags, in these I have a class definition like this:

<table>
  <tr>
    <th>No</th><th>Name</th>
  </tr>
  <tbody class="foo">
    <tr>
      <td>1.</td><td>One</td>       
    </tr>
  </tbody>
</table>

That was not valid XHTML according to the W3C Validator and it took me some time to figure out why. Now I've got it! One has to use the thead tag too if you want to use the tbody tag. Here's an example:

<table>
  <thead>
    <tr>
      <th>No</th><th>Name</th>
    </tr>
  </thead>
  <tbody class="foo">
    <tr>
      <td>1.</td><td>One</td>       
    </tr>
  </tbody>
</table>

Worth remembering.