Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b6pre) Gecko/20100907 Firefox/4.0b6pre ID:20100907041859 See post viewtopic.php?p=9848555#p9848555 and http://forums.mozillazine.org/viewtopic.php?p=9858761#p9858761 Black lines are there when scrolling the scrollable div (topic review). D2D state doesn't matter (happens with and w/o D2D), but layers.accelerate-all triggers the bug for me (if off, black lines disappear). Reproducible: Always Steps to Reproduce: 1. Start Minefield with new profile 2. Open ( http://forums.mozillazine.org/ ) and login 3. Write A POST REPLY and Preview 4. Scroll TOPIC REVIEW Actual Results: Black lines are there when scrolling the scrollable div (topic review). And the black line disappears in a few seconds. Graphics Adapter Description: ATI Radeon HD 4300/4500 Series Vendor ID: 1002 Device ID: 954f Adapter RAM: 512 Adapter Drivers: aticfx64 aticfx64 aticfx32 aticfx32 atiumd64 atidxx64 atiumdag atidxx32 atiumdva atiumd6a atitmm64 Driver Version: 8.762.0.0 Driver Date: 8-3-2010 Direct2D Enabled: true DirectWrite Enabled: true GPU Accelerated Layers Enabled: 1/1

screenshot http://img204.imageshack.us/i/55060893.jpg/

Windows 7 (32bit) Adapter Description : NVIDIA GeForce GTS 250 Vendor ID : 10de Device ID : 0615 Adapter RAM : 1024 Adapter Drivers : nvd3dum nvwgf2um,nvwgf2um Driver Version : 8.17.12.5896 Driver Date : 7-9-2010 Direct2D Enabled : true DirectWrite Enabled : true GPU Accelerated Layers Enabled : 1/1 Direct3D 9

This maybe fixed by Bug 593860

I can not reproduce the problem any more. http://hg.mozilla.org/mozilla-central/rev/36f5cf6b2d42 Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b6pre) Gecko/20100908 Firefox/4.0b6pre ID:20100908040849