Disable scrolling inside lightbox

but i think what you mean is not the scrollbar in the lightbox but that background of lightbox is scrollable:
(sometimes the content of the lightbox isnt an image but maybe a website or a lot of text – this should stay scrollable)

try this in functions.php of your child-theme:

add_action('wp_footer', 'custom_lightbox_script');
function custom_lightbox_script(){
?>
<script type="text/javascript">
(function($) {
    function a() {
      $('body').on('click', '.lightbox-added', function() {
        if($('.mfp-bg').length >= 1) {
          $('html').css("overflow-y", "hidden");
        } 
      });
      
      $('body').on('click', function() {
        setTimeout( function() {
          if($('.mfp-bg').length == 0) { 
            $('html').css("overflow-y", "scroll");
          }
        },500);   
      });
    }
  a(); 
})(jQuery);
</script>
<?php
}

hm ? :lol

Can’t wait to hear from you.

it seems that it is not so urgent as you said ;)

more than 2 weeks ago ?!

are there any problems understanding the above?
Is it how to install a child-theme ?
please talk to us – we only can help if we got input from you

thanks for response and feedback:
allthough i would like to know that i’m on a lightbox so maybe a little transpranency would be nice:
( but that’s up to you, of course – and a matter of preference )

.mfp-zoom-in.mfp-ready.mfp-bg, .mfp-zoom-in.mfp-ready.mfp-preloader {
    opacity: 0.9 !important;
    background: black !important;
}

By the way : on your website the directory listing is possible so i can search in your uploads folder and download the bigger files.
I don’t think this can be in your interest.
There are different ways to disable that – i use for that htaccess file.
f.e. with that Options All -Indexes
please inform yourself in detail, this is already a security risk

yes that code is for quick css and i guess this must be code with opacity:1 existing in your quick css already
(by default enfold got a opacity of 0.8)

By the way, I’m very impressed by your pictures;
unfortunately I use my photo equipment very little for creative purposes. I do quite a few art reproductions with my Nikon D850. I am convinced that I could photograph much more than Rhenish Impressionism with it ;)