Search filter window – Options list max height with more / less link

Hi guys,

I have just beed to this page from the showcase:
https://www.arbolife.com/en/directory/

And it has a real cool function. When I open the filter window for Restaurants for example in the Category are many things which is a long list. Intead of showing all the list / items at the end there is a “more” link that can be clicked and then shows off the rest of the Category items.

That is a GD function or a special customization?

Thx,
Atilla