606216 - box-shadow seems to contribute to layout

Status: RESOLVED DUPLICATE of bug 446693

(Core :: Web Painting, defect)

Description

[Robin Berjon]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-GB; rv:1.9.2.10) Gecko/20100914 Firefox/3.6.10
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-GB; rv:1.9.2.10) Gecko/20100914 Firefox/3.6.10

It appears that the box-shadow is taken into account for the size of a box when according to http://www.w3.org/TR/css3-background/#box-shadow it shouldn't be ("Shadows do not influence layout").

This can be seen with the attached test page. A div that has your normal 100%, when given a box-shadow, causes a horizontal scroll bar to show up. It shouldn't. Note that this happens even if the shadow is only vertical (the x offset is 0) if it has a blur, since the blur will bleed on the sides).

Reproducible: Always

Steps to Reproduce:
1. Style a box with a shadow.
2.
3.
Actual Results:  
It over-contributes in its size.

Expected Results:  
It ought to be truncated to the viewport (in this case, there may be a more general behaviour to match the spec).

Comment 1

[Robin Berjon]

Attachment: Test box-shadow on a full width box

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

fixed a few weeks ago