Thanks for your feedback but I think the key is not another theme. You have the following function in functions.php:
function catchbox_body_classes( $classes )
Here you set fullsize as CSS class. Example:
elseif ( is_page_template( ‘page-disable-sidebar.php’ ) || is_attachment() ) {
$classes[] = ‘singular’;
}
elseif ( is_page_template( ‘page-fullwidth.php’ ) || is_attachment() ) {
$classes[] = ‘fullwidth’;
}
Here I would like to add another template but this doesn’t work and I don’t understand why:
elseif ( is_page_template( ‘page-finder.php’ ) || is_attachment() ) {
$classes[] = ‘fullwidth’;
}