Not understanding should_close and will_parent_close usage

[analytik]

Hi,

I'm having trouble figuring out how to get should_close() to work as expected. I'm using Bevy + bevy_egui. What I want to do is "when user closes settings windows, persist settings to disk without having to press a dedicated Save button".

pub fn show_bg_conf_gui(
    mut contexts: EguiContexts, //etc
) -> Result {
    let ctx = contexts.ctx_mut()?;
    let foo = egui::Window::new("Background settings")
        .open(&mut gui_conf.is_bg_conf_open)
        .title_bar(true)
        .fade_in(true)
        .resizable(true)
        .movable(true)
        .collapsible(true)
        .show(ctx, |ui| {
            /* config window goes here */
            if ui.should_close() || ui.will_parent_close() {
                // doesn't work
                info!("Closing egui for bg conf");
            }
        });
    // doesn't work either
    if let Some(foowin) = foo {
        if foowin.response.should_close() {
            info!("Closing egui for bg conf! v2");
        }
    }
    Ok(())
}

Neither of those ever trigger. Is there a way to manually assign ClosableTag or did I miss some option in the ui builder to make it work? .closable() didn't exist on any of the objects I tried it on.