User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:2.0b6pre) Gecko/20100908 Firefox/4.0b6pre Build Identifier: Mozilla/5.0 (Windows NT 6.1; rv:2.0b6pre) Gecko/20100908 Firefox/4.0b6pre Problem arises when viewing flash contents with D2D enabled Upon scrolling (up/down), some parts of the flash content appears to be distorted. Reproducible: Always Steps to Reproduce: 1. Visit www.youtube.com 2. Pick any video you like 3. When the video is playing, try scrolling the webpage up/down Actual Results: You should notice that the player control is distorted. Though it appears to be functioning well, so you can play/pause, fast forward, rewind, etc. But you have to guess the location of the controls Expected Results: Simple. No distorted flash content. NOT every flash is affected. I only observed the flash from Youtube.com and Google Analytics is affected.

Mozilla/5.0 (Windows NT 6.1; rv:2.0b6pre) Gecko/20100913 Firefox/4.0b6pre You can scroll up and down the page, and you'll the video controls not repaint correctly, as seen in the attachment. Re-scrolling will usually make the problem go away.

Although bug 593839 calls out d3d explicitly, I think these two are related. In that bug just loading will show the problem. Here you have to scroll up and down.