WooCommerce, add customer mail to the order admin list.

woocommerce-overwrite-order-columns.php

<?php
/*
Plugin Name: WooCommerce Overwrite Order Columns
Plugin URI: 
Description: Adds the customers mailadress back to the order admin list.
Author: Mo
Version: 0.1
Author URI: 
*/
if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly
/**
 * Check if WooCommerce is active
 **/
if ( in_array( 'woocommerce/woocommerce.php', apply_filters( 'active_plugins', get_option( 'active_plugins' ) ) ) ) {

	/**
	 * Add new content to the "order_number" column
	 * We use a priority of 11 to add the new content after the default content, so the default content is kept.
   	 * After the default content we add the customer mail, as a clickable mailto link.
	 **/
	add_action( 'manage_shop_order_posts_custom_column', 'wcooc_add_to_order_number', 11, 2 );
	function wcooc_add_to_order_number( $column_name, $post_id ) {

		// Get an instance of the WC_Order object
		$order = wc_get_order( $post_id );

		// Get the Order data
		$order_data = $order->get_data(); 

		// Get the billing mailadress from the order data
		$order_billing_email = $order_data['billing']['email'];

		// Add content to default column "order_number"
	    if ($column_name == 'order_number') {
	    	echo '<a href="mailto:'.$order_billing_email.'" style="display:block;">'.$order_billing_email.'</a>';
	    }
	}

}//END WC check

Thank you. This info should never have been removed from the orders screen. You've just made my day finding this.