[airstrike]

When an event comes through a component's overlay (like picking an option in a pick_list), Component::update runs but the view is only rebuilt in diff, which invalidate_layout never triggers. If update returns no message, the old view stays on screen until something else rebuilds the interface.

use iced::Widget;
use iced::widget::{Component, column, component, pick_list, text};

pub fn main() -> iced::Result {
    iced::run(|_: &mut (), _: ()| {}, view)
}

fn view(_state: &()) -> impl Widget<()> {
    component(Picker)
}

struct Picker;

impl<'a> Component<'a, ()> for Picker {
    type State = Option<&'static str>;
    type Event = &'static str;

    fn update(
        &self,
        state: &mut Self::State,
        event: Self::Event,
        _renderer: &iced::Renderer,
    ) -> Option<()> {
        *state = Some(event);
        None
    }

    fn view(&self, state: &Self::State) -> impl Widget<Self::Event> + 'a {
        column![
            pick_list(*state, ["A", "B", "C"], ToString::to_string).on_select(|s| s),
            text!("Selected: {state:?}"),
        ]
    }
}

Picking an option leaves the text at None. Invalidating the widgets instead of the layout fixes it.