Scroll the page with some text selected and the selection doesn't move until the scroll stops.

https://www.youtube.com/watch?v=l3k_IxuoFcY

This is "caused" by the -webkit-over-scrolling:touch rule, but if we remove this rule the scrolling loses all its momentum which is probably worse.

The only element that appears to be allowed to have smooth touch scrolling and draw the selection continuously is the window itself, however on iOS we have to use a scroll container for other reasons (I think to keep the toolbar visible when the keyboard is up).