WP_Widget_Tag_Cloud::form( array $instance )

	public function form( $instance ) {
		$current_taxonomy = $this->_get_current_taxonomy($instance);
		$title_id = $this->get_field_id( 'title' );
		$count = isset( $instance['count'] ) ? (bool) $instance['count'] : false;
		$instance['title'] = ! empty( $instance['title'] ) ? esc_attr( $instance['title'] ) : '';

		echo '<p><label for="' . $title_id .'">' . __( 'Title:' ) . '</label>
			<input type="text" class="widefat" id="' . $title_id .'" name="' . $this->get_field_name( 'title' ) .'" value="' . $instance['title'] .'" />
		</p>';

		$taxonomies = get_taxonomies( array( 'show_tagcloud' => true ), 'object' );
		$id = $this->get_field_id( 'taxonomy' );
		$name = $this->get_field_name( 'taxonomy' );
		$input = '<input type="hidden" id="' . $id . '" name="' . $name . '" value="%s" />';

		$count_checkbox = sprintf(
			'<p><input type="checkbox" class="checkbox" id="%1$s" name="%2$s"%3$s /> <label for="%1$s">%4$s</label></p>',
			$this->get_field_id( 'count' ),
			$this->get_field_name( 'count' ),
			checked( $count, true, false ),
			__( 'Show tag counts' )
		);

		switch ( count( $taxonomies ) ) {

		// No tag cloud supporting taxonomies found, display error message
		case 0:
			echo '<p>' . __( 'The tag cloud will not be displayed since there are no taxonomies that support the tag cloud widget.' ) . '</p>';
			printf( $input, '' );
			break;

		// Just a single tag cloud supporting taxonomy found, no need to display a select.
		case 1:
			$keys = array_keys( $taxonomies );
			$taxonomy = reset( $keys );
			printf( $input, esc_attr( $taxonomy ) );
			echo $count_checkbox;
			break;

		// More than one tag cloud supporting taxonomy found, display a select.
		default:
			printf(
				'<p><label for="%1$s">%2$s</label>' .
				'<select class="widefat" id="%1$s" name="%3$s">',
				$id,
				__( 'Taxonomy:' ),
				$name
			);

			foreach ( $taxonomies as $taxonomy => $tax ) {
				printf(
					'<option value="%s"%s>%s</option>',
					esc_attr( $taxonomy ),
					selected( $taxonomy, $current_taxonomy, false ),
					$tax->labels->name
				);
			}

			echo '</select></p>' . $count_checkbox;
		}
	}