您可以检查post_status 查询变量并确保将其设置为trash:

function wpse239286_trash_column( $columns ) {

    // Bail if we\'re not looking at trash.
    $status = get_query_var( \'post_status\' );
    if ( \'trash\' !== $status ) {
        return $columns;
    }

    return array_merge( $columns, 
        array( \'trash_column\' => __( \'Trash Column\', \'text-domain\' ) )
    );
}
add_filter( \'manage_posts_columns\' , \'wpse239286_trash_column\' );
add_filter( \'manage_pages_columns\' , \'wpse239286_trash_column\' );