[css2.1] Propagation of CSS direction property to the initial containing block

The CSS 2.1 spec states in section 10.1.1:

"The 'direction' property of the initial containing block is the same as for the root element."

This is incomplete and doesn't really capture what browsers do.  For example, IE propagates the direction from the body to the ICB, and it even ignores the directionality specified on the root element (replacing it with the body's direction).

I'd like to propose that the spec mention that you can propagate from the body.

The behavior I just implemented in WebKit [1] propagates from the body to the root element if no explicit direction is set on the root element.  It then propagates the direction from the root element to the ICB.  This behavior is consistent with how backgrounds propagate (and is also similar to how overflow applies to the viewport as well).

Note that whatever we decide should apply to writing-mode also.

dave
(hyatt@apple.com)

[1] https://bugs.webkit.org/show_bug.cgi?id=48157