Header dont go under the custom header (Page Header)

Hi there,

Not sure you mean by kind of corrupting the viewport?

Are you adding the slider shortcode inside page header content?

No, I put the shortcode inside the page section. I'm using a plugin that gives you the possibility to create section that you can't put inside a fullpage container. That plugin uses a template page that has no <?php get header /?php> so I had one ( I used your code in the single.php files).

<?php
/**
 * The template for displaying all fullpages
 *
 * This is the template that displays all fullpages by default.
 * Please note that this is the WP Fullpage construct of fullpages and that
 * other 'pages' on your WordPress site will use a different template.
 */

get_header(); ?>

	<div id="primary" <?php generate_content_class();?>>
		<main id="main" <?php generate_main_class(); ?>> // This part is add 
			

<div id="fullpage" class="<?php WPFP_Query()->get_fullpage_easing(); ?> <?php print WPFP_Query()->fullpage->post_name; ?>" data-bg="<?php print WPFP_Query()->get_fullpage_bg(); ?>">

	<?php

		while ( have_posts() ) : the_post();

			// Start the sections Loop.
			WPFP()->get_sections();

		endwhile;

	?>

</div><!-- #fullpage -->

<?php

$navigation = WPFP_Query()->fullpage->fullpage_options['navigation'];

if( 'yes' === $navigation )
	WPFP()->get_navigation();

// WPFP()->get_sidebar();
WPFP()->get_footer(); 

Maybe I forgot to add some code to my template that creates this conflict.

This is the original parameter after I activate the custom header
.generate-combined-page-header {
height: 100vh;
}
But when I leave this as it is, the fullpage scroll is blocked by this parameter.
It's a plugin conflict for sure, but it's the only way I found out to implant the fullpage.js in WordPress. Can you help to find a solution ?

I don't really see the issue, but perhaps try this instead?:

.generate-combined-page-header {
    height: auto !important;
}

You can also just de-select the full screen option in the Page Header settings.