Created attachment 47778 [details] Reduction The timeline thumb on YouTube videos using a custom <video> controller leaves trails behind if the page is scrolled while the video is playing. This is apparently caused by a scroll event listener that forces layout, and can be reproduced with the attached reduction by scrolling it slowly, either by Option-dragging the scroller or scrolling with a Magic Mouse.
This happens in TOT as well as in Safari 4.0.4.
<rdar://problem/7611158>
Created attachment 49267 [details] Override -setNeedsDisplayInRect: and adjust the invalid rects during scrolling
Comment on attachment 49267 [details] Override -setNeedsDisplayInRect: and adjust the invalid rects during scrolling r=me I guess it's not possible to do a repaint test?
Fixed in <http://trac.webkit.org/projects/webkit/changeset/55159>.
Followup fix in bug 163154.