dreadstar42

added the code to my functions.php of my theme:

function add_custom_post_types( $query ) {
	if ( $query->is_search || $query->is_tag || $query->is_category ) {
		// print_r($query->query_vars);
		$query->set( 'post_type', array( 'post', 'custom1','custom2' ) );
		// echo "after set<br>";
		print_r($query->query_vars);
	}
}
add_action( 'pre_get_posts', 'add_custom_post_types' );

also, only one item of type custom1 is returned when I select a tag. Here is the print_r of the $query_vars on the Tag Archive page:

Array
(
    [tag] => lagarde
    [error] =>
    [m] =>
    [p] => 0
    [post_parent] =>
    [subpost] =>
    [subpost_id] =>
    [attachment] =>
    [attachment_id] => 0
    [name] =>
    [static] =>
    [pagename] =>
    [page_id] => 0
    [second] =>
    [minute] =>
    [hour] =>
    [day] => 0
    [monthnum] => 0
    [year] => 0
    [w] => 0
    [category_name] =>
    [cat] =>
    [tag_id] =>
    [author] =>
    [author_name] =>
    [feed] =>
    [tb] =>
    [paged] => 0
    [comments_popup] =>
    [meta_key] =>
    [meta_value] =>
    [preview] =>
    [s] =>
    [sentence] =>
    [fields] =>
    [menu_order] =>
    [category__in] => Array
        (
        )

    [category__not_in] => Array
        (
        )

    [category__and] => Array
        (
        )

    [post__in] => Array
        (
        )

    [post__not_in] => Array
        (
        )

    [tag__in] => Array
        (
        )

    [tag__not_in] => Array
        (
        )

    [tag__and] => Array
        (
        )

    [tag_slug__in] => Array
        (
            [0] => lagarde
        )

    [tag_slug__and] => Array
        (
        )

    [post_parent__in] => Array
        (
        )

    [post_parent__not_in] => Array
        (
        )

    [author__in] => Array
        (
        )

    [author__not_in] => Array
        (
        )

    [post_type] => Array
        (
            [0] => post
            [1] => custom1
            [2] => custom2
        )

)