Hey @astearns - So I've played with this a little to figure out how to make it not pass in FF. Since this test is specifically testing the case where clipping occurs (shape-margin extending beyond margin box), isn't that sort of fallback-type behavior and therefore expected to pass whether or not shapes is enabled?  It seems the common failure scenario would be where clipping did not occur and the text would then wrap to the shape-margin. In this test, the red would show up in this case.  I realize this is a bit screwy, so I'm open to suggestions on this one.