Focus not visualised on startup

import QtQuick
import QtQuick.Controls

ApplicationWindow {
    width: 800
    height: 700
    title: "activeFocusItem: " + activeFocusItem
    visible: true

    Row {
        Button {
            objectName: "testButton1"
            focus: true
            text: "Button 1"
        }
        Button {
            objectName: "testButton2"
            text: "Button 2"
        }
    }
}