[jQuery] jqueryui and nested tabs doesn't work

Hi all,

why when I call this $('#tabs-1').tabs('select', 1); tabs stop working?

What I'm doing wrong?

This is the right way to obtain nested tabs or are there other ways?

$('#tabs').tabs();
$('#tabs-1').tabs('select', 1);

<!-- Tabs -->
<div id="tabs">
<ul>
<li><a href="#tabs-1">First</a></li>
<li><a href="#tabs-2">Second</a></li>
<li><a href="#tabs-3">Third</a></li>
</ul>
<div id="tabs-1">
<ul>
<li><a href="#tabs-1a">First</a></li>
<li><a href="#tabs-1b">Second</a></li>
<li><a href="#tabs-1c">Third</a></li>
</ul>

<div id="tabs-1a">Lorem ipsum dolor sit amet ...</div>
<div id="tabs-1b">Lorem ipsum dolor sit amet ...</div>
<div id="tabs-1c">Lorem ipsum dolor sit amet ...</div>
</div>

<div id="tabs-2">Phasellus mattis tincidunt nibh. ...</div>
<div id="tabs-3">Nam dui erat, auctor a, dignissim quis, ...</div>
</div>

--
Massimiliano Marini - http://www.linuxtime.it/massimilianomarini/
"It's easier to invent the future than to predict it." -- Alan Kay