How exactly does the keymap feature work?

[mainrs]

The code suggests that the key I use to register my own keymap has to be the active key. Otherwise, the default keymap is used. However, there doesn't seem to be a way to change the active key.

I was hoping that the feature can be used to add additional behavior on user input. Like registering Ctrl-X to deselect all checkbox items.

My code:

pub trait PromptWithDefaultOptionsExt {
    fn register_reset_keymaps(self) -> Self;
}

impl PromptWithDefaultOptionsExt for Checkbox {
    fn register_reset_keymaps(self) -> Self {
        self.register_keymap("a", handle_edit_event)
    }
}

#[tracing::instrument(skip(renderer))]
fn handle_edit_event(
    event: &Event,
    renderer: &mut promkit::preset::checkbox::render::Renderer,
) -> anyhow::Result<PromptSignal> {
    match event {
        Event::Key(KeyEvent {
            code: KeyCode::Char('x'),
            modifiers: KeyModifiers::CONTROL,
            kind: KeyEventKind::Press,
            state: KeyEventState::NONE,
        }) => {
            debug!("clearing checkbox state");
            renderer.checkbox_state.checkbox.clear(); // forked to add this method myself.
        },
        _ => {},
    }

    Ok(PromptSignal::Continue)
}

Is what I am trying to achieve currently possible? What exactly is the keymap feature intended to do?