Qml Combobox not closing when delegate of the listview goes out of scope

I have made a delegate for listview that contains Combobox. If I open the Combobox and scroll the listview, the Combobox popup is moving with the delegate position, that's ok. But when the delegate goes out of the listview area(Ref the sample image attached), Combobox popup continues to moves even out of the listview area.

How to close the Combobox when the corresponding delegate goes out of the listview area.

Thanks in advance...

Code goes here

import QtQuick 2.9
import QtQuick.Window 2.2
import QtQuick.Controls 2.2

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

    Column {
        spacing: 0
        anchors.fill: parent
        Item {
            width: parent.width
            height: parent.height * 0.4
            Image {
                anchors.fill: parent
                anchors.margins: 10
                source: "https://lh4.googleusercontent.com/proxy/cITVCAj9KJ5Hfwd5iuNDhzdB2pSrMQv2rzTl-vvg23Ifhe2qdCisZBG-MzV35y_r2zijC9X4QOpda9eHzr_hA"
            }
        }
        ListView {
            width: parent.width
            height: parent.height * 0.7
            model: 10
            spacing: 5
            clip: true
            delegate: Rectangle {
                width: parent.width
                height: 50
                color: index % 2 == 0 ? "lightsteelblue" : "steelblue"
                Row {
                    spacing: 25
                    anchors.centerIn: parent
                    Label {
                        text: qsTr("%1").arg(index)
                        anchors.verticalCenter: parent.verticalCenter
                    }
                    ComboBox {
                        anchors.verticalCenter: parent.verticalCenter
                        model: ["a", "b", "c"]
                    }
                }
            }
        }
    }
}