Created attachment 542627 [details] screencast of bug STEPS TO REPRO: 1. Load https://webfwd.org/ 2. Hit PageDown or End key 3. Hit PageUp or Home key RESULTS: Some significant fraction of the time, a large black/gray-gradient oval flashes on the website, behind "What is Web Fwd?", for 1 frame, and then disappears. See attached testcase. Not sure if it's a website bug or a gecko bug. Pascal suggested filing a gecko bug, so I'm filing it here for now. (Pascal: I'm not sure if you directly work on the site, but if not, perhaps you could CC someone who does? I'm hoping that they might be able to provide a static and/or reduced testcase, so that we can still test this down the road after the website is changed)
Ping me if anyone needs something from me. The website was created by Andy Chung - he's happy to help as well.
Confirmed against Mozilla/5.0 (Windows NT 5.1; rv:7.0a1) Gecko/20110629 Firefox/7.0a1 ID:20110629030813 Mozilla/5.0 (Windows; U; Windows NT 5.1; de; rv:184.108.40.206) Gecko/20110614 Firefox/3.6.18 ID:20110614230723 Opera 11.50 Build 1074, though there it's a Rectangle instead of an Oval. WFM against Google Chrome 14.0.806.0.
New site doesn't show this bug anymore.