CSS: negative 'margin-top:' in percent ignored

[Jeroen Op 't Eynde]

Overview & Results:

Bug appears on http://xprsyrslf.be/ in the menu animation.
<div id="menu"> is initialy set to 'margin:-25%;' and gets animated by javascript.
Bug also gets reproduced without javascript.

Working with pixels instead of percents, works!
See http://xprsyrslf.be/testing_webkit.php
All percents are set to something in pixels here.

Steps to Reproduce:

Use negative percents for 'margin-top:' in your css.

Build Date & Platform: 

Build 2009-08-01 on Arch Linux (kernel: 2.6.30.2)
Webkit from svn: 46646-1 (Midori, Arora)
Latest Chromium build (don't know webkit version)

[Jeroen Op 't Eynde]

Created attachment 33920 [details]
html file showing this bug

initial: no text visible
only without 'overflow:hidden;' on html,body: text visible but no 'margin-top:'
only without ' position:relative;' on div#ctr: seems to be fixed but attribute is mandatory for other elements to be working

[Jeroen Op 't Eynde]

Attachment became irrelevant, probably shows a bug in Opera/Presto and not Webkit.

[Ahmad Saleem]

Report seems to indicate that it was a bug in Opera/Presto rather than Webkit. Marking as "RESOLVED INVALID". Thanks!