Taxonomy Filter to Admin List https://wordpress.org/support/topic/add-taxonomy-filter-to-admin-list-for-my-custom-post-type

wp_filterable_taxonomy_backend.php

function restrict_books_by_genre() {
        global $typenow;
        $post_type = 'wohnheim'; // change HERE
        $taxonomy = array('wohnmoeglichkeiten', 'region', 'traeger'); // change HERE
        if ($typenow == $post_type) {
            $selected = isset($_GET[$taxonomy]) ? $_GET[$taxonomy] : '';
            $info_taxonomy = get_taxonomy($taxonomy);
            wp_dropdown_categories(array(
                'show_option_all' => __("Alle Wohnheimkategorien {$info_taxonomy->label}"),
                'taxonomy' => $taxonomy,
                'name' => $taxonomy,
                'orderby' => 'name',
                'selected' => $selected,
                'show_count' => true,
                'hide_empty' => true,
            ));
        };
    }

    add_action('restrict_manage_posts', 'restrict_books_by_genre');

    function convert_id_to_term_in_query($query) {
        global $pagenow;
        $post_type = 'wohnheim'; // change HERE
        $taxonomy = array('wohnmoeglichkeiten', 'region', 'traeger'); // change HERE
        $q_vars = &$query->query_vars;
        if ($pagenow == 'edit.php' && isset($q_vars['post_type']) && $q_vars['post_type'] == $post_type && isset($q_vars[$taxonomy]) && is_numeric($q_vars[$taxonomy]) && $q_vars[$taxonomy] != 0) {
            $term = get_term_by('id', $q_vars[$taxonomy], $taxonomy);
            $q_vars[$taxonomy] = $term->slug;
        }
    }
    
    
    
    
    
    // https://gist.github.com/mikeschinkel/541505
    function my_restrict_manage_posts() {
    global $typenow;
    $args=array( 'public' => true, '_builtin' => false ); 
    $post_types = get_post_types($args);
    if ( in_array($typenow, $post_types) ) {
    $filters = get_object_taxonomies($typenow);
        foreach ($filters as $tax_slug) {
            $tax_obj = get_taxonomy($tax_slug);
            wp_dropdown_categories(array(
                'show_option_all' => __('Show All '.$tax_obj->label ),
                'taxonomy' => $tax_slug,
                'name' => $tax_obj->name,
                'orderby' => 'term_order',
                'selected' => $_GET[$tax_obj->query_var],
                'hierarchical' => $tax_obj->hierarchical,
                'show_count' => false,
                'hide_empty' => true
            ));
        }
    }
}
function my_convert_restrict($query) {
    global $pagenow;
    global $typenow;
    if ($pagenow=='edit.php') {
        $filters = get_object_taxonomies($typenow);
        foreach ($filters as $tax_slug) {
            $var = &$query->query_vars[$tax_slug];
            if ( isset($var) ) {
                $term = get_term_by('id',$var,$tax_slug);
                $var = $term->slug;
            }
        }
    }
}
add_action('restrict_manage_posts', 'my_restrict_manage_posts' );
add_filter('parse_query','my_convert_restrict');