scrolling inside the iframe should not scroll the host page when you get to the bottom.

This is a really annoying behavior of browsers in general where you scrolling something inside a container and then you get to the bottom and the whole page scrolls so that thing were looking at is outta sight.

Start by locating the iframe and its scroll-container handling in the live-editor frontend, then reproduce the behavior by scrolling to the container's bottom. Done means reaching either end of the iframe's content no longer propagates scrolling to the host page; verify the behavior in a browser.

Written by the indexing model from the issue text.