Hi,
I have created a pen here: https://codepen.io/Snippet/pen/jENzYVo
Basically the list has a .active item (green color) and this .active class changes on scroll, so I need that upon scrolling the general window the .active item is centered on the overflowed list so that it shows at the middle of the visible area always without recurring to applying display:none to the other elements.
For example this is what I mean by centered:
Did some pregress : updated pen fork: https://codepen.io/Snippet/pen/ByBrJqE