&gt; Meaning the sidebar has to follow my finger, at 60fps, as I quickly swipe in and out. If such a thing is as easy you claim then a quick demo should be easy enough.<p>So what you want to do is to install a touch event handler and adjust a transform. Assume that the sidebar is pre-rasterized to a layer via will-change.<p>In this case, the DOM manipulation is going to be 1µs or so. Style recalculation, 1ms at most (this is a huge overestimate). Layout is skipped since you are animating a transform. Paint is skipped since you&#x27;re animating a transform, the element is layerized, and all tile contents are cached. Compositing, 3ms at most (also probably a huge overestimate). Even with the most pessimistic possible numbers, I can&#x27;t get anywhere near 16ms for this workload.