<div id="sidebar">
		<div id="category-list">
		    <ul id="topnav">
		        <?php

		            global $post;
		            $postcategories = get_the_category();
					$postcategory = $postcategories[0]->cat_ID;
		            $pid = $post->ID;
		            $post_categories = wp_get_post_categories( $post->ID );
		            $cats = array();
		            foreach($post_categories as $c){
		                $cat = get_category( $c );
		                $cats[] = $cat->ID;
		            }
		            $active_cat_count = true;
		            $cat_count = 0;


		        $kategorien = get_categories(array(
		        'child_of' => 0,
		        'exclude_tree' => 15,
		        'exclude' => 16,
		        'orderby' => 'slug',
		        'order' => 'ASC'));
		            foreach($kategorien as $kategorie) {
		            if (isset($active_cat_count) && $active_cat_count){
		                if (in_array($kategorie->ID,$cats)){
		                    $active_cat_count = false;
		                }else{
		                    $cat_count = $cat_count + 1;
		                }
		            }
		            $cat = $kategorie->cat_ID;
		            echo '<li class="cid-'. $cat .'"><a href="#" class="category-title">'; echo ($kategorie->name); echo '</a>';
		                echo '<ul>';
		                    $posts = get_posts('category='. $cat .'&posts_per_page=-1');
		                        foreach($posts as $post) { ?>
		                        <li>
		                            <a <?php if ($post->ID == $pid) echo 'class="current"'; ?> href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
		                        <li>
		                    <?php }
		                echo '</ul>';
		       	 echo '</li>';
		            }
		        ?>
		    </ul>
		</div>

		<script>
		$("#topnav").accordion({
			closedSign: '+',
    		openedSign: '-',
    		active: '.cid-<?php echo $postcategory; ?>'
		});
		</script>


				<span>Post-Kategorie-ID: <?php echo $postcategory; ?></span>

		<?php
			if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar() ) :
		endif; ?>
</div><!-- #sidebar -->