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Re: [CSS21] Does 'clear' apply to caption box? (corrected link)

From: Daniel Schattenkirchner <schattenkirchner.daniel@gmx.de>
Date: Thu, 10 Jan 2013 21:16:42 +0100
Message-ID: <50EF21AA.5080807@gmx.de>
To: www-style@w3.org
On 09/01/2013 16:36, Anton Prowse wrote:
> On 08/01/2013 23:42, Daniel Schattenkirchner wrote:
>> On 08/01/2013 22:08, Anton Prowse wrote:
>> CSS 2.1, 9.4.1: http://www.w3.org/TR/CSS2/visuren.html#block-formatting
>> [...], block containers (such [...] table-captions) [...] establish new
>> block formatting contexts for their contents.
>> So Gecko is correct in this regard.
> No, that's a misreading of that (awkwardly worded) sentence, which
> should actually be read as:
>    # [...] block containers (such as [...] table-captions) *that are not
> block boxes*, [...] establish new block formatting contexts for their
> contents.

I see. According to CSS 2.1 a table-caption is a block box and lives in 
a BFC (the table wrapper box), so you would not expect captions to 
establish a BFC by themselves.

Between April and November 2006 table-captions were added to this sentence:
> [...], table-captions, [...] establish new block formatting contexts.

I didn't got back any further. The sentence was changed to its current 
state between September 2009 and December 2010. I think it was an 
unintended change to make it ambiguous whether table-captions do 
establish a BFC or not.

> Table-captions are blocks and so are excluded.  It's confusing that
> they're even mentioned in that paragraph.  At one point in the past I
> think captions /did/ establish BFCs, and so that mention of them
> probably goes back years.  That particular paragraph has been debated a
> lot, and what we've currently got is probably best described as an
> uneasy compromise.  I'm pretty sure I have proposed changes to that
> paragraph for some of the open bugs, in which I've removed the mention
> of the captions.
> That said, if there is strong inter-op for captions establishing a BFC
> then it could be considered for errata, but that's a different story.
> Though I do seem to recall WG solution on this a few years ago, as part
> of deciding whether the table wrapper box establishes a BFC.

Firefox 18, Opera 12.12, Chrome 23 and IE10 beta on Win7 all establish a 
BFC for captions. WebKit's multiple captions bug has also been fixed, 

If neccessary, an errata should clarify this behaviour.

Daniel Schattenkirchner
Received on Thursday, 10 January 2013 20:17:03 UTC

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