[Jayx]

Basically the exact same thing, without the slide effect. IOW you have a nav that targets elements in another the div, which you place inside a div that hides the overflow. The problem is that the id that you're targeting will try to align with the top of the browser window, causing the page to jump upwards as it does so; unless the page content doesn't reach the bottom of the window and therefore doesn't need to scroll.

I have tried sticking everything inside an iframe (just in case), but it doesn't try to jump to the top of the iframe only, again it tries to align to the top of the browser window.