#6: wp_terms_checklist_args

wp_terms_checklist_args.php

<?php
/**
 * Disable 'checked_ontop' for Media Categories taxonomy
 *
 * @see wp_terms_checklist()
 * 
 * @param array $args An array of arguments.
 * @param int $post_id The post id.
 *
 * @return array The arguments array.
 */
function wpdocs_no_top_float( $args, $post_id ) {
  // If the taxonomy is set and equals 'media_cats'
	if ( isset( $args['taxonomy'] ) && 'media_cats' == $args['taxonomy'] )
		$args['checked_ontop'] = false;

	return $args;
}
add_filter( 'wp_terms_checklist_args', 'wpdocs_no_top_float', 10, 2 );

http://fotd.werdswords.com/wp_terms_checklist_args/