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Re: z-index

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Thu, 18 Jul 2002 23:27:28 -0400
Message-Id: <200207190327.XAA22285@nerd-xing.mit.edu>
To: "Sigurd Lerstad" <sigler@bredband.no>
cc: www-style@w3.org

> And a new stacking context is created on the root and when a positioned
> element has something else than auto? (Just to make sure I've read the spec
> correctly)

Yep.

> But in my example, if the <em> had z-index: 1, then it would be correct to
> overlap the second <p> (and everything else on the *entire* page that had
> z-index below 1?)

Yes.

> So there would be two stacking contexts on the page, one for the root
> element, and one for the <em>?

Yes.

> Introducing z-index, I should keep a tree/hierachy of the stacking
> levels also, where each stacking context keeps a list of the boxes
> that belong to that stacking-context and draw recursively the
> stacking-contexts ? Would something like that result in the correct
> rendering?

It sounds reasonable.... (but I've not really thought about it very
hard. ;)).

> And the fact that other browers do it incorrectly, is that because they
> always increase the stack level of absolutely positioned elements? (even if
> auto is specified for z-index)

I can't speak for all of them.  In Mozilla it's basically because
positioned things are in a separte rendering object list...

> > Last I heard, the WG was going to attempt address this issue (possibly
> > by making an erratum to the z-index section).
> 
> By this you mean, change the spec to accomodate browsers?

Basically, yes.  As has already happened to a certain extent with clip,
for example, and as happened with underscores in identifiers.

Boris
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Received on Thursday, 18 July 2002 23:27:31 GMT

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