That's true for traditional object oriented GUI, but there are other ways to do it. Druid uses almost no interior mutability, and Arc is used sparingly, as immu

That's true for traditional object oriented GUI, but there are other ways to do it. Druid uses almost no interior mutability, and Arc is used sparingly, as immutable data structures are very handy for incremental computation. The Crochet prototype is even more imgui-like from the perspective of the application, and relies on Arc (and Clone bounds) even less. I think doing this right will require some imagination, not just playing greatest hits from previous decades, only in a new language.