Should overlay close when its ancestor scrolls?

[hunterloftis]

We decided yes not too long ago: #2736

But since then we've seen at least one use-case where an overlay was wanted to stay open during scrolling.

/cc @Westbrook @najikahalsema

[pwong09]

It would be great to keep the overlay open, but its sizing should be static when user scrolls outside of the overlay - maybe add an attribute for height size (s, m, l)?