Persistent chat was originally a separate column (so it didn't overlap with anything on the page) but was brought into the main page recently.

I don't immediately have any great ideas to fix this in a clean way -- @chad, maybe you have some better ideas?

• We could put a spacer at the bottom of the page when the chat panel is open so you can always scroll the chat window past the page content, but it would have to be fairly tall if the chat window has been expanded. This might look and feel awkward, and the scrollbar will become somewhat misleading (i.e., the document will look taller than it actually is, so the scrollbar won't be as good a predictor of how much content is left).
  • We could do this, but max the spacer height at the collapsed chat height. This feels pretty questionable to me since it means you sometimes need to collapse chat, click something, then expand chat again.
• We could make chat auto-hide if you scroll to the bottom of a page, but I think intent will be unclear in some cases and this interaction might not feel very good. In particular, if the document fits completely in one window, there's no way for us to distinguish between "scrolled to the top" and "scrolled to the bottom".