Re: [CSS21] stack level definitions in 9.9.1

Sylvain Galineau wrote:
> The proposed edits are as follows; they are meant to be accepted or
> rejected as a whole:

[snip the six edits]

Great!

> The set of proposed changes is somewhat larger than I originally intended
> but you have convinced me of their coherence. I believe them to be sufficient
> for this revision of the spec. 

I'm very happy with the content and scope of the proposals; they address
and satisfactorily resolve all the technical (as opposed to editorial)
problems in 9.9.1, as well as making a couple of useful editorial
clarifications to Appendix E.  Specifically, they solve 2.7, 2.8 and
2.10 in my original analysis[1] which describe problems with the
definition of stack level, the handling of positioned elements with
z-index:auto, the superfluous "local stacking context" concept, and the
behaviour of floats and their descendants.

Whilst you may have wished for a smaller set of changes, I think that
what we've got is in fact the most elegant and succinct approach
possible in solving the technical problems.  I've attached a document
highlighting the proposed changes within the full text of 9.9.1 (also
available at [2]) in which we can see that they only amount to a few
words here and there.

I have one tiny niggle with your proposed edit #4:

> 4. In section 9.9.1 [2], replace:
>       # The contents of inline blocks and inline tables are stacked as if
>       # they generated new stacking contexts, except that any positioned
>       # elements and any elements that actually create new stacking contexts
>       # take part in the parent stacking context. They are then painted atomically
>       # in the inline stacking level.
>    with
>       # The contents of positioned elements with 'z-index: auto',
>       # non-positioned floats, inline blocks and inline tables are
>       # stacked as if they generated new stacking contexts, except that
>       # any positioned elements and any elements that actually create
>       # new stacking contexts take part in the parent stacking context.
> 

Perhaps we should insert "and of" at the end of the first line, as in

| The contents of positioned elements with 'z-index: auto', and of
| non-positioned floats, inline blocks and inline tables...

since otherwise I don't think it's clear that "non-positioned" also
qualifies inline blocks and inline tables in that proposal.  Or
perhaps even spell it out and repeat "non-positioned" twice more in that
sentence.

Niggle aside, I'm happy to put Issue 60[3] to rest now.  Of the
remaining issues in my original analysis, I agree that 2.1–2.6 are of a
sufficiently non-technical nature that they are probably better
addressed in future levels of CSS, whilst 2.9 is obsoleted by the
current proposal and 2.11 (typo in 9.5 Floats) has already been resolved
as Issue 60a.[4]

[1] http://dev.moonhenge.net/css21/spec/z-index/
[2]
http://dev.moonhenge.net/css21/spec/z-index/css21_zindex_proposal3_ap-sg.html
[3] http://wiki.csswg.org/spec/css2.1#issue-60
[4] http://wiki.csswg.org/spec/css2.1#issue-60a

Cheers,
Anton Prowse
http://dev.moonhenge.net