Layout.verticalStretchFactor does not work

import QtQuick
import QtQuick.Layouts

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")

    ColumnLayout {
        anchors.fill: parent

        Rectangle {
            Layout.fillWidth: true
            Layout.fillHeight: true
            Layout.verticalStretchFactor: 3
            color: "green"
        }

        Rectangle {
            Layout.fillWidth: true
            Layout.fillHeight: true
            Layout.verticalStretchFactor: 1
            color: "blue"
        }
    }
}