Re: [csswg-drafts] [css-multicol] Margin collapsing does not make sense with column-spans.

@aethanyc Thanks for fixing that!

@rachelandrew Thanks. I'm not going to the F2F, BTW.

I still don't understand why columns (or fragmentainers in general) should establish a BFC, or what a BFC means for a fragmentainer. Fragmentainers don't capture floats, for instance, which BFCs are supposed to. I also don't understand what it solves to define them as BFCs. It would make slightly more sense if it were the column *rows* that establish BFCs, since they will be layout siblings of the spanners. But that would still not be quite right, since rows may be adjacent siblings (a multicol container laid out across several pages, for instance), and the float capturing gets confusing again.

But I don't think I understand the problem with spanners and margin collapsing. Spanners vs. column rows in a multicol context is very similar to regular blocks vs. lines in non-fragmented layout. Of course, block margins on inline elements don't collapse with anything (they don't even grow the line).

Spanners do not participate in the fragmentation context, like column content does.

Would it help to introduce an anonymous wrapper in the spec, similar to what we have in CSS2 when blocks are siblings of inline boxes (then we wrap the inline boxes inside an anonymous block)? I.e. wrap column content inside a wrapper, which becomes a sibling of the spanners? The wrapper could establish a BFC and a fragmentation context and do multicol layout, while the spanners are on the outside (and the actual multicol container parent will just do regular block layout, consisting of spanners and anonymous multicol wrappers). Does this make sense?

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Received on Thursday, 11 October 2018 08:28:15 UTC