> What is it that matters for "immediate mode"? Is it that the UI renders everything every frame? No. It's that you build the UI by describing what it should look like everyframe, based only (or mostly) on the data. This is why React won...

I don't think that's why React got so popular. React popularized unidirectional data flow, which is different than immediate mode rendering. This readme file seems to conflate the two of those.

Now that I think of it, couldn't one argue that React itself is a retained mode UI, since it choses which components to re-render and which not to?