User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b9pre) Gecko/20110101 Firefox/4.0b9pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b9pre) Gecko/20110101 Firefox/4.0b9pre There is a white gradient in the left and right frame of all aero glass windows. The gradient begins at about a 40% distance from the top of the window with a white colour stop. Then, the gradient ends at about 20% from the top with a transparent colour stop. This gradient can sometimes move, and this usually happens on tab panorama. Reproducible: Always Steps to Reproduce: 1. Restore the window if the window is currently maximised. 2. Look at the position of the gradient. 3. Open Tab Panorama. 4. Move the group that the current active tab is inside of. Whilst doing this, you will be able to see the bug. Actual Results: The colour gradient moves up and down. Expected Results: The colour gradient is static.