See the Cards examples for Material Design [1]. There's no single linear layout but multiple ones in different directions and anchors. There can also be images and multi-line text.

For another example: Adwaita's boxed lists [2] are pretty complex. Blender generally uses a simple label followed by some kind of button, in comparison Adwaita has a wrapping box, separator, special handling for first/last items, subtitles, animated expansion, and a ton of customizability.

I'm not saying these are good examples of UI, but they are surely _more complex_ than Blender. Blender has more menus and controls compared to a normal Material/Adwaita UI for sure, but they are pretty much the same, so it has quantity but not complexity from my point of view.

    [1]: https://m2.material.io/components/cards#anatomy
    [2]: https://gnome.pages.gitlab.gnome.org/libadwaita/doc/1.4/boxed-lists.html

It is a matter of how we define complexity.

I think BUI stands out because of the intricate nesting and relational binding there is between elements and not only a lot of state, but precedents and context.

About intricacies, BUI can render css in its own engine, so if material UI widgets are necessary, it's just html layouts and css.

I think it accomplishes both kind of "intricate UI". I concede I haven't tried to see how material would render with it though, as it claims impressive performance, I doubt everything is GPU optimized, as even css itself doesn't have full coverage GPU optimisations in any of its browser implementations

both of these examples look fairly trivial. they can easily be implemented in almost any ui toolkit.

to me, the complexity of a UI comes from the state management. imagine if the data for those cards is sourced from multiple places, with various rules, and can also be updated from multiple places. how do you keep it all in sync?

imgui's eliminate that almost entirely.