Go to Vimeo in HTML5 mode, hit Play on the video, mouse off the button. Note the line of blue pixels remaining at the top of the button.
Created attachment 182862 [details] Screenshot
<rdar://problem/13020054>
Does not reproduce on windows or linux at any zoom level, seems to be mac specific.
Also, this would be a particularly strange *repaint* issue. When the button animates in and out, the cruft remains.
(In reply to comment #4) > Also, this would be a particularly strange *repaint* issue. When the button animates in and out, the cruft remains. The buttons render into a compositing layer, and that layer gets animated in and out. So it's still a repaint issue within that compositing layer.
I can't repro any more.
Awesome news!