Hi Steve, yes all projects are just running without any problems, so no news for a long time

Here some code for the user-column:

// add extra column to users
//
add_filter( 'manage_users_columns', 'usersColumn' );
function usersColumn( $columns ) {

	$new = array();
	foreach ( $columns as $key => $title ) {
		if ( $key == 'posts' ) // Put the  column before this column
		{
			$new['quiz_count'] = 'Aantal lessen';
		}
		$new[ $key ] = $title;
	}

	unset( $new["posts"] );

	return $new;

}

// add value to the extra  vraag post_type column
//
add_filter( 'manage_users_custom_column', 'manage_users_custom_fields', 10, 3 );
function manage_users_custom_fields( $val, $column_name, $user_id ) {

	//$user = get_userdata( $user_id );
	switch ( $column_name ) {

		case 'quiz_count' :

			$args        = array(
				'posts_per_page'   => - 1,
				'offset'           => 0,
				'category'         => '',
				'category_name'    => '',
				'orderby'          => 'date',
				'order'            => 'DESC',
				'include'          => '',
				'exclude'          => '',
				'meta_key'         => '',
				'meta_value'       => '',
				'post_type'        => 'dquiz',
				'post_mime_type'   => '',
				'post_parent'      => '',
				'author'           => $user_id,
				'post_status'      => 'publish',
				'suppress_filters' => TRUE
			);
			$posts_array = get_posts( $args );

			return count( $posts_array );
			break;
		default:
	}

	return $val;
}

// Make it sortable
//
add_filter( 'manage_users_sortable_columns', 'users_sortable_column' );
function users_sortable_column( $columns ) {

	$columns['quiz_count'] = 'quiz_count';
	return $columns;
}

It creates the column, and makes it sortable.
I didnt post the actual ‘ordering’ query. But no need for this here.
It just didnt show any value, when the “show IDS” was enabled in the helpers-plugin.