Scrolling through a file with sticky scrolling enabled:

without:

It looks like there are more dropped frames when sticky scrolling is enabled.

A rendering frame looks like this with sticky scrolling disabled:

And like this with sticky scrolling enabled:

(u seems to be StickyScrollWidget._renderRootNode)

I think the slow Recalculate Style comes from reading the layout in line 339:

Can you cache this somehow? I don't know why reading this property causes this additional layout (because I thought the browser would do this layout anyway). Maybe Alex can also help here.