428634 - overflow:hidden messes up proper floating

Status: RESOLVED DUPLICATE of bug 377664

(Core :: Layout, defect)

Description

[Jeffrey D. King]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9b5) Gecko/2008032619 Firefox/3.0b5
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.5; en-US; rv:1.9b5) Gecko/2008032619 Firefox/3.0b5

if the first of two divs is floated left, and the second is given a left margin greater than the width of the first div, the distance between the divs should be the difference between the assigned margin and the width of the first div.  However, when the second div is assigned "overflow:hidden", the distance between the divs is equal to the entire margin (not reduced by the width of the first div).

Reproducible: Always

Steps to Reproduce:
1.go to http://test.kingdesk.com/firefox-float-bug/
2.copy the source
3.remove the "overflow:hidden" from the css
4.it will display as it should
5.re-enter "overflow:hidden"
6.it displays in error
Actual Results:  
I was able to make the distance between the two divs improperly change.

Expected Results:  
The distance between the divs should not change, and should always be the value of the left margin less the width of the first div.

That is pretty much it.

Comment 1

[philippe (part-time)]

Gecko used to be correct in this, until the wording of CSS 2.1 9.5 changed from 'margin-box' to 'border-box' (last paragraph before the example)
http://www.w3.org/TR/CSS21/visuren.html#floats

See bug 377664 for the details.