[onion2k]

It's not virtualized. It's not even a list. It's a very large SVG with lots of foreignObject bits in it. The app is a diagramming tool - imagine Visio but for lawyers to map out contracts and ownerships between hundreds of corporations.

[Davertron]

Sorry, someone else mentioned a virtual list component and I assumed it was you without looking at the username.

That's pretty impressive, I've run into perf issues with far fewer actual DOM nodes than that!

[JMTQp8lwXL]

You might get better performance with the <canvas> element instead of SVG. I've noticed React can struggle with SVGs containing complex subtrees.