RE: [CSS2.1] table container behavior (captions, floats and margin collapsing)

As promised, here are two options for updating the spec (http://www.w3.org/TR/CSS21/tables.html#model)

Option 1 (make the anonymous box a block formatting context):

“The anonymous box is a 'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level
<DEL>, except that this block is never considered as a block for 'run-in' interaction, and that </DEL>
<INS>The anonymous box establishes a block formatting context.</INS>
The table box (not the anonymous box) is used when doing baseline vertical alignment for an 'inline-table'.”

            Also, the illustration will need to change to remove margin collapsing requirement.

Option 2 (block formatting context, keep margin collapsing):

“The anonymous box is a 'block' box if the table is block-level, and an 'inline-block' box if the table is inline-level
<DEL>, except that this block is never considered as a block for 'run-in' interaction, and that </DEL>
<INS>The anonymous box establishes a block formatting context. The top margin of the first top caption and the bottom margin of the last bottom caption collapse with the margins of the multi-column element as per the normal rules for collapsing. That includes honoring ‘clear’ property if set on the first top caption.</INS>
The table box (not the anonymous box) is used when doing baseline vertical alignment for an 'inline-table'.”

(the margin collapsing clause it taken literally from CSS3 multicol, with added requirement for ‘clear’. Multicol says nothing about clear, FF and Safari implementations don’t honor clear on the first element in multicol, so it would probably be fine to say clear is ignored… but it seems to make sense to include clear in margin collapsing)