598290 - Scrolling corrupts display by overwriting what was already there (new in FF 4 beta 5 or so)

Status: RESOLVED WORKSFORME

(Core :: General, defect)

Description

[Ed Avis]

User-Agent:       Mozilla/5.0 (Windows NT 5.1; rv:2.0b6) Gecko/20100101 Firefox/4.0b6
Build Identifier: Mozilla/5.0 (Windows NT 5.1; rv:2.0b6) Gecko/20100101 Firefox/4.0b6

See the attached HTML page and screenshot, and the 'reproduce' notes below.

Reproducible: Always

Steps to Reproduce:
1. Load the attached HTML file in Firefox 4 beta 5 or beta 6.

2. Scroll up and down by dragging the scrollbar on the right.

Actual Results:  
The screen shows a superposition of text from different parts of the file.

Expected Results:  
Correct scrolling to a different part of the document.

I believe this is a relatively new bug, since I did not observe this display corruption with Firefox 3.6 or earlier, nor with early betas of Firefox 4.

Here's the 'Graphics' section of about:support:

Adapter Description: Matrox Millennium G450 DualHead DVI PCI - English
Vendor ID: 102b
Device ID: 0525
Adapter RAM: Unknown
Adapter Drivers: G400DHD
Driver Version: 5.93.9.0
Driver Date:
Direct2D Enabled: false
DirectWrite Enabled: false

Comment 1

[Ed Avis]

Attachment: HTML page reproducing the bug, gzip compressed

Please gunzip and view in browser.  Sorry it's so big.

Comment 2

[Ed Avis]

Attachment: Screenshot showing the incorrect rendering

Comment 3

[Benjamin Smedberg]

A 25MB testcase isn't really minimized or that useful for debugging. Unless this starts hitting less-contrived sites, it's not a blocker. Please renominate if necessary.

Comment 4

[Ed Avis]

I agree the test case is not very minimal.  Were you able to reproduce the bug, however?  If not I'll do some more testing on different machines.

Comment 5

[Wayne Mery (:wsmwk)]

I cannot reproduce