Issue 142: http://wiki.csswg.org/spec/css2.1#issue-142

Reported by Boris Zbarsky

10.1 (Definition of "containing block") uses the term "ancestor box", but it is unclear whether this is used with regard to the formatting structure or the document tree.

Two of the three occurrences of this term (which only appears in 10.1) seem to be replaceable by "ancestor element".  The third, that in list item 2:
  # 2. For other elements, if the element's position is 'relative'
  #    or 'static', the containing block is formed by the content
  #    edge of the nearest block container ancestor box.
is unclear; as he outlines in his second proposal, Bert is unhappy with "block container element", I think because the defined term is "block container box".


Issue 142: http://wiki.csswg.org/spec/css2.1#issue-142

URL
    http://lists.w3.org/Archives/Public/www-style/2009Sep/0126.html #4
Summary
    clarify terms like "ancestor box", whether referring to formatting structure or document tree. Spec contains only three instances of ancestor box. They are all in section 10.1.
Resolution
    Agreed this is ambiguous.
Proposal
    first version [http://lists.w3.org/Archives/Public/www-style/2010Aug/0436.html];
    second version with support for run-in [http://lists.w3.org/Archives/Public/www-style/2010Oct/0042.html]
Follow-up 1
    There is probably an error [http://lists.w3.org/Archives/Public/www-style/2010Oct/0044.html] in the resolution of issue 120 [http://wiki.csswg.org/spec/css2.1#issue-120]. If so, the proposal needs changing.
Follow-up 2
    Boris Zbarsky asks [http://lists.w3.org/Archives/Public/www-style/2010Aug/0443.html] that the containing block of an element inside a table, in the absence of a table element, be created from the height of the row and the width of the column, even if one or both of those are implied rather than actual elements. If we accept that change, the proposal needs changing.
    This issue should be treated separately; it is filed as Bug 15671.