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Re: [csswg-drafts] [css-contain] Is it ok that contain:layout is a CB for fixpos/abspos descendants but doesn't establish a stacking context?

From: Daniel Holbert via GitHub <sysbot+gh@w3.org>
Date: Thu, 26 Jul 2018 19:52:21 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-408215421-1532634740-sysbot+gh@w3.org>
>  Some of the stacking context triggers do not imply containing block for abs pos. Opacity is one example.

Ah, thank you - that's a good counterexample.  So the two groups aren't 100% equivalent as I'd initially stated, but rather: one group is a subset of the other. Let me restate my observed "rule" more carefully, with that in mind:

Up until now, if an element forms a containing block for abs pos descendants, then that always implies it is in this special "is positioned or forms stacking context" category that's referenced several times in the painting spec.  (And there are a few other things in that category, like "opacity" as you noted.

`contain:layout` would be the first (I think?) exception to this "rule" -- it forms an abs pos containing block, but it's not in the special "is positioned or forms stacking context" category.

> However, I think that making contain:layout a stacking context would be a good change

Great! I'm glad we're in agreement. Thanks for chiming in.

GitHub Notification of comment by dholbert
Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/2942#issuecomment-408215421 using your GitHub account
Received on Thursday, 26 July 2018 19:52:24 UTC

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