Hello Bas,
They are using a different theme so we are not certain how they are able to achieve it.
But as for X/Pro, you can achieve it by doing a bit of customization.
First is to create a Global Block with the header contents.
Once the global block is created, you will get a corresponding shortcode for the global block.
Next. make sure that you have the child theme installed and activated. Then login through FTP and go to wp-content/x-child then edit the functions.php file and add this code:
function single_post_header() {
if ( is_single() ) {
echo do_shortcode('[cs_gb id=41]');
}
}
add_action('x_after_masthead_end', 'single_post_header');
Please change [cs_gb id=41]
to the actual shortcode of the global block you have created.
Hope this helps.