392026 - getBoundingClientRect returns different value than IE when scrolled

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Mike Sullivan]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a7) Gecko/2007080210 GranParadiso/3.0a7
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9a7) Gecko/2007080210 GranParadiso/3.0a7

Gran Paradiso (Alpha 7) implements getBoundingClientRect differently than Internet Explorer, regarding behavior when the page is scrolled. 

IE's rect.top value is relative to the top of the viewport (visible section of the page). 
Gran Paradiso's rect.top value is relative to the top of the page itself. 

This can easily be seen if you scroll this page in IE so that the link is nearer to the top. It's rect.top value changes. Gran Paradiso's does not.

This may also occur with horizontal scrolling, though that doesn't affect us as much.

Reproducible: Always

Steps to Reproduce:
See the attached file. Test in IE and Gran Paradiso.

1. Click the demonstration link without scrolling. IE and GP return similar things.
2. Scroll the window so that the link is very close to the top.
3. Click the link again. IE and GP return very different results.
Actual Results:  
GP's value is always the same. IE's changes.

Expected Results:  
I'd expect the behavior to be equivalent to IE's.

Comment 1

[Mike Sullivan]

Attachment: Test case for the getBoundingClientRect problem

Comment 2

[Mark Wubben]

I can confirm this problem.

Comment 3

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I fixed this a while ago.