[jQuery] Simple selector not working in 1.3.1 and webkit (safari and chrome)

[jQuery] Simple selector not working in 1.3.1 and webkit (safari and chrome)

I'm creating a component for an application I'm developing and I have upgraded jquery to the last version to get it's speed boost.
After some testing I have seen that my component is not working correctly in webkit browsers because there is some bug with the new Sizzle selector of the new jquery.
I can't provide my source files, but I have created a simple test case that shows this error.
<div style="margin-left: 40px;"><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
    "<a href="http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd</a>">
<html xmlns="<a href="http://www.w3.org/1999/xhtml">http://www.w3.org/1999/xhtml</a>" xml:lang="en" lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <script type="text/javascript" src="jquery.js"></script>
    <script type="text/javascript">
        $(function() {
            var container = $('#container');
            var containerSelecteds = function() {
                return container.find('ul.selected');
            };
            var bodySelecteds = function() {
                return $('ul.selected');
            };
            var select = function(nodes) {
                containerSelecteds().removeClass('selected');
                nodes.addClass('selected');
                // the container html show me that the element has the class "selected"
                alert(container.html());
                // webkit (chrome and safari) says that there are no elements inside of <container> with the class "selected"
                alert(containerSelecteds().length);
                // but the element exists in the dom, and it has the classname "selected" !!
                alert(bodySelecteds().length);
            };
            var element = $('<ul class="someclass"><li>MyText</li></ul>').appendTo(container);
            select(element, false);
        });
    </script>
</head>
<body>
    <div id="container" style="border:1px solid #ccc;height:300px;width:300px"></div>
</body>
</html>
</div>
I will try to explain the error: I'm inserting a node inside the "container" div, and applying a classname "selected" to this node. After this, I want to select the nodes inside "container" that have this classname. Firefox, IE, etc, says that there is one node inside "container". But webkit browsers says that there is a node with this classname in the dom, but not inside "container".
I think that this is a quite simple css selector, so I don't know why it fails.
Thanks.
PD: it doesn't fails with jquery 1.2.6