[CSS21] Issue 70 (collapsing margins and block formatting contexts)

Resulting from discussion in the face-to-face on 2008-08-22,[1, 2] a 
decision was made to change 8.3.1 to state that vertical margins of 
block formatting contexts do not collapse with their in-flow 
children.[3]  (Apparently this arose from discussion of Issue 14.[4])

Prior to the decision, it was well-known (if not explicitly mandated) 
that block formatting contexts were /not/ excluded from such margin 
collapsing.[5]

To my knowledge this change wasn't discussed on this mailing list, and 
whilst I have no objection to the decision I would be interested to hear 
the thoughts of those involved in it, as it has a direct impact on 
recently-discussed ideas on a possible need for in-flow block-level 
neutral block formatting contexts.[6]

Cheers,

Anton Prowse
http://dev.moonhenge.net

[1] http://lists.w3.org/Archives/Public/www-style/2008Sep/0075.html (See 
section entitled "CSS2.1 Issues")
[2] http://lists.w3.org/Archives/Public/www-style/2008Sep/0077.html
[3] http://wiki.csswg.org/spec/css2.1#issue-70
[4] http://wiki.csswg.org/spec/css2.1#issue-14
[5] http://lists.w3.org/Archives/Public/www-style/2005Jan/0104.html (A 
clear explanation of the issue by Ian Hickson.)
[6] http://lists.w3.org/Archives/Public/www-style/2008May/0262.html

Received on Wednesday, 29 October 2008 20:07:28 UTC