SwitchDelegate's handle is not draggable

import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Controls 2.0

ApplicationWindow {
    id: window
    width: 360
    height: 360
    visible: true

    Column {
        spacing: 20
        anchors.centerIn: parent

        Switch {
            text: "Switch"
        }
        SwitchDelegate {
            text: "SwitchDelegate"
        }
    }
}