In none of them text is primary and all other incidental?
> What UI frameworks don't do this?
In which UI framework actions like "set focus on an element" triggers a full page re-layout?
Also, in which UI framework there's even a discussion of "try to not trigger re-paint/re-flow"?
And yes, I know about immediate mode UI where the entire layout is re-calculated every frame. But then they can usually render thousands of elements at 60fps.
> In none of them text is primary and all other incidental?
This is a pretty outdated way of thinking. If we were only speaking about (old) HTML then maybe. But these days HTML and CSS are basically inseparable and go far beyond "text is primary".
> In which UI framework actions like "set focus on an element" triggers a full page re-layout?
I don't see why a browser would need to re-layout for just a focus change. Unless, of course, the CSS changes require a re-layout after the focus has changed (`:focus` selector).
Every UI framework can run into performance issues with layout and/or painting if they're complex enough (or poorly made). There is fundamentally very few differences between HTML+CSS and other UI frameworks.
And how is that different from a UI framework?
> Almost every single interaction and change requires the browser to recalculate the layout of the entire page and to redraw it.
What UI frameworks don't do this?