WebEngineView upon resizing shows ugly blue background

import QtQuick 2.15
import QtQuick.Controls 2.15
import QtWebEngine 1.15
ApplicationWindow {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")
    WebEngineView {
        id: webview
        anchors.fill: parent
        backgroundColor: "black"
    }
}