275366 - margin just gets colored when border

Status: RESOLVED INVALID

(Core :: Layout, defect)

Description

[Bernhard Kraft]

I found out the following:
If you have a <DIV class="outer">
which has assigned a background-color, and in it another DIV
<DIV class="inner"> which hasn't got a background-color but a margin,
then the margin's of this inner DIV just get colored when the outer
DIV has borders.
In the example on the URL "http://www.libelle.at/kraftb/moz_bug.html" you
can see it.
If you look at the source you see the "border-top" of the outer DIV is commented
out. If you comment it in the margin of the inner DIVs will also get colored 
blue.

Comment 1

[Ray Papworth]

Attachment: text with padding

I think this is correctly rendered according to the recommedations of
http://www.w3.org/TR/REC-CSS2/box.html
The effect is caused by collapsing margins. See bug 275388.
Using padding rather than margin as in the attachment should achieve the effect
you want. (I.E. gives the same result with your original example, but is
arguably wrong in this case)

Comment 2

[Mats Palmgren (inactive)]

"... adjoining margins (no non-empty content, padding or border areas or
clearance separate them) of two or more boxes (which may be next to one another
or nested) combine to form a single margin."
http://www.w3.org/TR/CSS21/box.html#collapsing-margins

-> INVALID

Comment 3

[Mats Palmgren (inactive)]

*** Bug 307016 has been marked as a duplicate of this bug. ***