Re: [csswg-drafts] [css-contain] `contain` should not affect `display`

You're correct that "used-value time" transformation of boxes doesn't make any sense. This also directly conflicts with our "two types of box-tree fix-up" that we're maintaining in Display (computed-value 'display' fixing, and anonymous box creation).

> Then it goes on to define a concept of “becoming a formatting context”, but doesn't explain how this is different from “establishing a formatting context” (which is an established term of art that has a specific meaning as defined in the Display glossary and CSS2.1), nor how that works.

Some elements define that they establish a formatting context; there is no general definition of how to *make* an arbitrary element establish a formatting context. More specifically, some layout types don't have a "formatting context" concept, but we need to be able to generate one for them to make layout and paint containment work.

The current spec's intention is to just bail out easy, by forcing elements that aren't already FCs into becoming either block or inline flow-roots, which are FCs and satisfy the condition. There's probably a smarter way to do it; this is tracked in #1457 already.

(This issue is technically a duplicate of #1457, then.)

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Received on Wednesday, 5 July 2017 20:54:33 UTC