258241 - Firefox does not collapse outer table margins with margins of table or other blocks

Status: RESOLVED DUPLICATE of bug 87277

(Core :: Layout: Block and Inline, defect)

Description

[Andreas Schildbach]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040803 Firefox/0.9.3
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7) Gecko/20040803 Firefox/0.9.3

Please look at the example attached. There are two div blocks and two table
blocks below. All blocks have a margin of 8px.

The margins of the div blocks collapse as per CSS2 specification (8px space
between the two divs).

However, the margins of the table blocks do not, and the margins of the mixture
div/table also does not (16px space).

IE6 does display this correctly (hard to believe... :-)


Reproducible: Always
Steps to Reproduce:
1. just look at the example with Firefox 0.9.3

Actual Results:  
see details

Expected Results:  
the 4 blocks should all have an equal distance of 8px

Comment 1

[Andreas Schildbach]

Attachment: html testcase for collapsing margins bug

Comment 2

[William James Dean]

I can see the bug. =>layout?

Comment 3

[Boris Zbarsky [:bzbarsky]]

From http://www.w3.org/TR/CSS21/box.html#collapsing-margins :

  Two or more adjoining vertical margins of block boxes in the normal flow
  collapse.

Note that the word "block" is a link to
http://www.w3.org/TR/CSS21/visuren.html#block-box which says:

  Block-level elements (except for display 'table' elements, which are described
  in a later chapter) generate a principal block box

In other words, display:table elements do not generate a "block box".  Margins
collapse only for block boxes.  So I believe our behavior is in fact correct. 
David, am I reading this right?

Comment 4

[dolphinling]

I think you're reading it wrong, Boris.

http://www.w3.org/TR/CSS21/tables.html#q2
table (In HTML: TABLE)
    Specifies that an element defines a block-level table: it is a rectangular
block that participates in a block formatting context.

Comment 5

[dolphinling]

...But this is a dupe anyway. 

*** This bug has been marked as a duplicate of 87277 ***