Drawer/Popup does not center in parent

import QtQuick 2.12
import QtQuick.Window 2.12
import QtQuick.Controls.Material 2.12
import QtQuick.Controls 2.12

import QtQuick.Controls.Material.impl 2.12

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

    Component.onCompleted: popup.open()

    Popup {
        id: popup
        dim: true
        modal: true
        width: 300
        height: 300
        anchors.centerIn: parent

        Button {
            anchors.centerIn: parent
            highlighted: true
            text: "Open"
            onClicked: drawer.open()
        }

        Rectangle {
            id: wrapper
            color: "gray"
            height: 50
            anchors {
                right: parent.right
                left: parent.left
                bottom: parent.bottom
            }
            Text {
                text: qsTr("Should center here")
                anchors.centerIn: parent
                color: "white"
            }
            Drawer {
                id: drawer
                modal: false
                dim: false
                interactive: false
                height: 40
                width: 300
                edge: Qt.BottomEdge

                //  ###### Popup documentation:
                anchors.centerIn: parent

                // Also not working
                // anchors.centerIn: wrapper
                // This generates
                // qrc:/main.qml:45:13: QML Drawer: Popup can only be centered within its immediate parent or Overlay.overlay
                // but it should be the same as parent

                // Anchors provide a way to position an item by specifying its relationship with other items.
                // A common use case is to center a popup within its parent. One way to do this is with the x and y properties. Anchors offer a more convenient approach:
                //  Pane {
                //      // ...
                //      Popup {
                //          anchors.centerIn: parent
                //      }
                //  }
                Button {
                    onClicked: drawer.close()
                    text: qsTr("close")
                    anchors.centerIn: parent
                }
                background: Rectangle {
                    radius: 4
                    color: Material.color(Material.LightBlue)
                    layer.enabled: true
                    layer.effect: ElevationEffect {
                        elevation: 6
                    }
                }
            }
        }
    }
}