Fix for messing up the global $post object on a write screen

global-post-snafu.php

<?php
function meta_box_callback( $post_local ) {
	global $post;
	$post_global_copy = $post;

	$my_query = new WP_Query( array(
		'posts_per_page' => 10
	) );

	if ( $my_query->have_posts() ) {
		while ( $my_query->have_posts() ) {
			$my_query->the_post();	// This causes the global $post object to change
		}
	}

	$post = $post_global_copy;
}