Run-in Boxes

Run-in header

The run-in header should appear to be a part of this paragraph.

The run-in header should appear to be a part of this text, since this text is an anonymous block box, and is thus a block box.

This is a right-floating box.

The run-in header should flow into this paragraph, not the float. (Or should it not run in at all? The wording of the spec is unclear.)