Co-authors can't delete/trash posts

[mecraft]

The first author of a post has the ability to delete it (depending on status, etc), but co-authors can't. Wordpress checks the capability "delete_others_posts" for co-authors, even though they're an "author". Basically, to the co-author, the option to "Move to Trash" is not displayed.

A functional workaround: the co-author can rearrange the authors to make themselves the first author, save, then delete the post.

I added the following fix for our environment. It may not work properly with other environments/workflows.

function allow_coauthor_delete($allcaps, $cap, $args) {
	if ($cap[0] === 'delete_others_posts') {
		if ($allcaps['delete_others_posts'] == true) {
			return $allcaps;
		}
		if (current_user_can('edit_post', $args[2])) {
			$allcaps['delete_others_posts'] = true;
		}
		return $allcaps;
	}
	return $allcaps;
}
add_filter('user_has_cap', 'allow_coauthor_delete', 10, 3);

I don't know if this is the best way to fix this.