I've been searching for a "lightbox" type solution that allows this but haven't found one yet (please, suggest if you know of any).
The behavior I'm trying to recreate is just like what you'd see at Pinterest when clicking on an image. The overlay is scrollable (as in the whole overlay moves up like a page on top of a page) but the body behind the overlay is fixed.
I attempted to create this with just CSS (i.e. a div overlay on top of the whole page and body with overflow: hidden), but it doesn't prevent div from being scrollable.
How to keep the body/page from scrolling but keep scrolling inside the fullscreen container?
Source: Stackoverflow.com