Fix for missing shadow on navigation list items

function fix_wp_shadow() {
?>
<script>
jQuery(document).ready( function($) {
    $("#adminmenuwrap").prepend("<div id='adminmenushadow'></div>");
});
</script>
<?php
}
add_action('admin_footer', 'fix_wp_shadow');

http://wordpress.org/plugins/wp-admin-classic/