The elements to which unicode-bidi:isolate applies

The current definition<http://dev.w3.org/csswg/css3-text-layout/#unicode-bidi>of
unicode-bidi:isolate states:

"For the purposes of the Unicode bidirectional algorithm, the contents of
the element are considered to be inside a separate, independent paragraph,
and for the purpose of bidi resolution in its containing paragraph (if any),
the element itself is treated as if it were an Object Replacement Character
(U+FFFC). (If the element is broken across multiple lines, then each box of
the element is treated as an Object Replacement Character.)"

I think that it is worthwhile to stipulate that unicode-bidi:isolate has no
effect whatsoever on any element that either creates a separate UBA
paragraph, or serves as a UBA paragraph break in its containing UBA
paragraph. Such elements include: any element taken "out of flow" e.g. with
float or position:absolute, any element with display other than "inline",
<br bidibreak=hard>, <textarea>, <input type="text">. This stipulation is
particularly important for the display:block and <br bidibreak=hard>
elements, for whom unicode-bidi:isolate's specification that the element be
treated in the containing paragraph as if it were U+FFFC, i.e. bidi class
ON, conflicts with the proposed
specification<https://docs0.google.com/a/google.com/document/edit?id=1zR06HjhVvt7ySAJeqq7zQZSzpLTRgV8AoQNo_vNznX4&pli=1&authkey=CIXomoYI#>that
these element be treated in the containing paragraph as if they were
bidi class B.

Thus, <div dir=auto> still serves as a UBA paragraph break between what
follows and precedes it despite having ubi by default. Same for the (less
useful, but theoretically possible) <br ubi>.

Aharon