This text should be visible, and the user should be able to scroll to read the text below. (This is also true with the containing block proposal. However, with Ian's proposal for overflow, the text below should be visible initially and there should be no scrolling mechanism.)
This text should NOT be visible initially, but the user should be able to scroll to see it. (This is also true with the containing block proposal. However, with Ian's proposal for overflow, it should be visible initially.)