Button hot state is not properly shown for children of Scroll

[xStrom]

This can be seen with the list example, especially if the debug_paint_layout is turned off. Hover over a button and then scroll a bit. The button should no longer have a white border but it does.

[richard-uk1]

I've just come across this problem. Repro example below.

use druid::widget::{List, Scroll, Switch, WidgetExt};
use druid::{AppLauncher, Widget, WindowDesc};
use im::{vector, Vector};

fn build_widget() -> impl Widget<Vector<bool>> {
    Scroll::new(List::new(|| Switch::new())).vertical().center()
}

pub fn main() {
    let window = WindowDesc::new(build_widget).title("Scroll evt error");
    AppLauncher::with_window(window)
        .use_simple_logger()
        .launch(vector![false])
        .expect("launch failed");
}

It requires both the list and the scroll - it is not present with either on its own.

[richard-uk1]

I'm doing a stream of consciousness at https://xi.zulipchat.com/#narrow/stream/255910-druid-help/topic/Event.20for.20window.20lost.20focus