Jami0

You are right, no issue with the demo (Opera).

There is just one other plugin on the page what could cause this issue: “Meteor Slides” (using jQuery).

It seems the pagescroll is preventing the browser-scroll multiple times, every time it flickers/scrolls down a bit and back to the top (many times in just one second). After that it scrolls down to the id. Sometimes flickering while scrolling, sometimes not.

It´s a combination of two plugins wich combined causing this issue.
Great support by the way. I never thought to get an answer that fast.

Searched and tried so many things for about 3 hours but now I found it (maybe some1 else can use this) – its so simple:

$all_wp_pages = get_pages();
  $children = get_page_children( get_the_ID(), $all_wp_pages );

🙂