Re: [CSS2.1] Clarifying 8.3.1 Collapsing Margins

On 07/28/2010 08:45 PM, L. David Baron wrote:
> On Wednesday 2010-07-28 20:01 -0700, fantasai wrote:
>>   | Two margins are adjoining if and only if:
>>   |   * no non-empty content, padding or border areas; line boxes;
>>   |     or clearance separate them
>>   |   * both belong to normal-flow block-level boxes in the same block
>>   |     formatting context
>
> Strictly speaking, we don't define what block formatting context an
> element is "in"; we only define that certain elements establish new
> block formatting contexts.  This means that technically, it's
> ambiguous whether an element that establishes a new block formatting
> context is in the BFC that it establishes.  In general, I think it
> makes more sense to say that it is (or, at the very least, that it's
> certainly not associated with any *other* block formatting context).
> However, this statement assumes that it is not.
>
> I think it is probably worth rewording to clarify this.

Changed "in" to "that participate in". I don't think it makes sense
for an element that establishes a new block formatting context to
be considered as /in/ the BFC that it establishes, though it could
reasonably be said to /contain/ that block formatting context.
Certainly it does not "participate" in the block formatting context
it establishes: it participates in its parent's block formatting
context, if it participates in a block formatting context at all.

>>   | Note. Adjoining boxes may be generated by elements that are not
>>   | related as siblings or ancestors.
>
> "adjoining margins" rather than "adjoining boxes"?

Yep.

~fantasai