suggestion for hierchical dropdown

term dropdown select

case 'taxonomy_select':
                    $names= wp_get_object_terms( $post->ID, $field['taxonomy'] );
					$terms = get_terms( $field['taxonomy'], 'hide_empty=0' );
                    $selected = '';
					foreach ( $terms as $term ) {
						if (!is_wp_error( $names ) && !empty( $names ) && !strcmp( $term->slug, $names[0]->slug ) ) {
							$selected = $term->slug;
						} else {

						}
					}               
                    wp_dropdown_categories(array('selected' => $selected,'taxonomy' => $field['taxonomy'], 'hide_empty' => false, 'hierarchical' => 1, 'id' => $field['id'], 'name' => $field['id'],'walker' => new Mfields_Walker_Taxonomy_Dropdown() ));
					echo '<p class="cmb_metabox_description">', $field['desc'], '</p>';
					break;


//added this at the bottom of init.php
/* Custom version of Walker_CategoryDropdown */
class Mfields_Walker_Taxonomy_Dropdown extends Walker {
	var $db_fields = array(
		'id'     => 'term_id',
		'parent' => 'parent'
		);

	var $tree_type = 'category';

	function start_el( &$output, $term, $depth, $args ) {

		$selected_terms = array();
		if ( isset( $args['selected'] ) ) {
			$selected_terms = (array) $args['selected'];
		}

		$selected = '';
		if ( in_array( $term->slug, $selected_terms ) ) {
			$selected .= ' selected="selected"';
		}

		$text = str_repeat( '&nbsp;', $depth * 3 ) . $term->name;
		if ( $args['show_count'] ) {
			$text .= '&nbsp;&nbsp;(' . absint( $term->count ) . ')';
		}
		if ( $args['show_last_update'] ) {
			$text .= '&nbsp;&nbsp;' . gmdate( __( 'Y-m-d', 'mfields-taxonomy-widget' ), $term->last_update_timestamp );
		}

		$class_name = 'level-' . $depth;

		$output.= "\t" . '<option' . $selected . ' class="' . esc_attr( $class_name ) . '" value="' . $term->slug . '">' . esc_html( $text ) . '</option>' . "\n";
	}
}