functions.php

<?php

/**
 * Add theme support for event categories
 * @author Bill Erickson
 * @link http://www.billerickson.net/code/be-events-calendar-categories
 */
function be_event_theme_support() {
	add_theme_support( 'be-events-calendar', array( 'event-category' ) );
}
add_action( 'after_setup_theme', 'be_event_theme_support' );