[jQuery] UL Hover menu

[TJ]

Hi there,

I'm trying to create a hover dropdown many with jQuery and all seems
to work fine in safari but not in ie7?

The idea is that when I hover over the main li the sub ul appears and
slides down. When I hover over the main li is works as planned but
then on ie7 when I move the mouse down to the sub ul is slide back
up???

jQuery:

<script type="text/javascript">
        $(document).ready(function() {
                // hide sub menus
                $('ul.col_one_subnav').hide();
                // toggle sub menus on hover
                $('.col_one_navigation li').toggle(function() {
                        $(this).children('ul:hidden').slideDown();
                        }, function() {
                        $(this).children('ul:visible').slideUp();
                });
        });
</script>



HTML:

<ul class="col_one_navigation">
                        <li><a href="" title="">Blackboard</a>
                                <ul class="col_one_subnav">
                                <li><a href="" title="">Blackboard</a></
li>
                                <li><a href="" title="">Blackboard</
a></li>
                                <li><a href="" title="">Blackboard</
a></li>
                            </ul>
                        </li>
                        <li><a href="" title="">Placements</a></li>
                        <li><a href="" title="">Student Union</a></li>
                    </ul>

Can anyone help.

Thanks.

TJ