Hmm.. Is this possible please?

Hi!

I have my graduate guide advice tip site here:

Business Bird

…and am having some thoughts on navigation!

I would like the posts under each category to be listed vertically underneath when the category is clicked on in the ‘Pick a Category’ sidebar box.

When two categories are opened up I would like the other to close so the left hand bar does not get over crowded.

I have this is my sidebar.php-

<?php // Menu for subpages of current page
		// Only shows if the current page has subpages
		if($post->post_parent) {
			$parent = wp_list_pages("title_li=&include=".$post->post_parent."&echo=0");
			$children = wp_list_pages("title_li=&child_of=".$post->post_parent."&echo=0");
		} else {
			$parent = wp_list_pages("title_li=&include=".$post->ID."&echo=0");
			$children = wp_list_pages("title_li=&child_of=".$post->ID."&echo=0");
		}
		if ($children) {
			echo '<h3 class="pages">Sub Pages</h3>';
			echo '<ul class="navigation">';
			echo $parent;
			echo $children;
			echo '</ul>';
		} // End Subpage menu ?>

        <?php // Category Navigation ?>
        <h3 class="folder">Skill Topics</h3>
        <ul id="navigation">
          <?php wp_list_categories('depth=2&title_li='); ?>
        </ul>
        <?php if (is_single() && function_exists('related_posts_by_category')) {
			$home = get_bloginfo("home");
			echo '<h3 class="related">Related Articles</h3>';
			echo '<div id="related">';
			echo '<ul>';
			related_posts_by_category(
			  array(
				'orderby' => 'post_date',
				'order' => 'DESC',
				'limit' => 5,
				'echo' => true,
				'before' => '<li>',
				'inside' => '',
				'outside' => '',
				'after' => '</li>',
				'rel' => 'nofollow',
				'type' => 'post',
				'message' => '<li><a href="'.$home.'">Sorry, no matches.</a></li>'
			  )
			);
			echo '</ul>';
			echo '</div>';
		}?>

Could you please let me know if there is more code hidden somewhere?

Thank you!!

Leon