User-Agent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8.1.2) Gecko/20070219 Firefox/2.0.0.2 Build Identifier: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.8.1.2) Gecko/20070219 Firefox/2.0.0.2 Because a table display type is "table" and not "block," I believe the rendering engine is not collapsing a table's vertical margins with an adjacent header tag. IE and Safari get it right as far as I can tell from the specs. In the css spec under "block-level elements and block boxes" the table display type is categorized as a block-level element so I am relatively sure this behavior is incorrect. If I change the display css attribute of the table to "block," the margin collapse issue is fixed, but the table renders incorrectly (obviously). Reproducible: Always Steps to Reproduce: 1. create an in-flow header with margin: 20px and the rest default. 2. create an in-flow table with margin: 20px and the rest default. Actual Results: There is a 40px space between the header and the margin. Expected Results: There should be a 20px margin between them, because they should collapse according to the spec AFAICT.

Have you tried a trunk build? Lots of reflow/layout/rendering work has been done on it. 3.0a3 @ http://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/latest-trunk/

Dupe of bug 87277 ?

Yes, I would resolve it as a dup of bug 87277 although this bug involves margin collapsing between a block-level element (<h1>) and a nextSibling table while bug 87277 refers to tables as consecutive siblings. It's still adjacent in-flow block-level elements..

CONFIRMING, marking as NEW Marking as dependent on bug 50959 Component: Layout: Tables Version: trunk URL field updated

I'm not sure .. maybe Component should be instead/rather Layout: Block and Inline Seamonkey 2.0a1pre rv:1.9b3pre build 2008010102 under XP Pro SP2 and Firefox 2.0.0.11 fail the test case at provided URL.

Table generate anonymous block box, but table can't collapse with this box, because table is not block level element.

Note sure why this was marked "depends on" bug 87277; it should be a duplicate. The problems both boil down to "table box margins don't collapse like normal blocks" and the solutions both boil down to "make table box margins collapse like normal blocks".