275388 - background clipped at bottom or top if no border

Status: RESOLVED INVALID

(Core :: Layout, defect)

Description

[Laurent Martelli]

In the following example, the background is not painted above and under the <p>
as it should. Add a border or a padding to the DIV, and it will be painted.

Comment 1

[Laurent Martelli]

Attachment: test case

Comment 2

[Ray Papworth]

This seems odd but I think the example is being rendered correctly. This is a
case of collapsing margins between nested blocks according to the
recommendations http://www.w3.org/TR/REC-CSS2/box.html

The <div> is given the same margin as the <p>, (as can be seen by the space at
the top of the page) and the background colour is only in the div's containing
block, not its margin.
If the div has a border then the margins are no longer adjacent so do not collapse.
(I.E does the same)

Comment 3

[Laurent Martelli]

(In reply to comment #2)
> The <div> is given the same margin as the <p>, (as can be seen by the space at
> the top of the page) and the background colour is only in the div's containing
> block, not its margin.
> If the div has a border then the margins are no longer adjacent so do not
collapse.
> (I.E does the same)

Still, I think it's very weird that the margin of the <p> collapses with the 0
width margin of the <div> and that the later "wins" (the p's margin is
transfered to the div's margin).

I would argue that a 0 width margin is not margin, so the there's nothing to
collapse with.

The specs says nothing about 0 width margin. I'll drop a message on [e-mail]

Comment 4

[Ray Papworth]

Attachment: text with padding

It seems the margin property should be used only to ensure sufficient space
between objects; then margin collapsing is logical. If you want some text with
a coloured area round it you can use padding as in the example.

Comment 5

[Mats Palmgren (inactive)]

Adjoining margins always collapse, even if they happen to have zero length.
http://www.w3.org/TR/CSS21/box.html#collapsing-margins

-> INVALID