To reproduce: 1. Go to http://annevankesteren.nl/ 2. Make the window more than 2000px wide 3. Hover over the sidebar links When the hover animation occurs, the "SVG SUCKS" text in the sidebar shifts upwards by one pixel. It shifts back into place when the animation finishes.
The page enters compositing mode for the duration of the animation. When the window is more than 2000px wide, we used a tiled layer for WebView::m_backingLayer.
<rdar://problem/8876819>
@Anne - your website might have changed a lot since past. I think we can close this bug as now? :-)
It actually hasn't really changed (though I did change the text from SVG sucks), but it appears to work fine these days. WebKit changed!