Make ComboBox popup expand to largest item or screen width

import QtQuick 2.15
import QtQuick.Window 2.15
import QtQuick.Controls 2.12
import QtQuick.Layouts 1.3

ApplicationWindow {
    id: window
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    RowLayout {
        width: parent.width

        Label {
            Layout.fillWidth: true
            text: "Select:"
        }

        ComboBox {
            model:  ["First", "Second longer", "Third even longer text"]
            Layout.fillWidth: false
        }
    }
}