StackView: pushing the already topmost item visually clears the stack

import QtQuick 2.7
import QtQuick.Window 2.2
import QtQuick.Controls 2.0

ApplicationWindow {
    id: mainWindow
    visible: true
    StackView
    {
        id: stackView
        anchors.fill: parent
        initialItem: redRect
    }
    Button
    {
        anchors.centerIn: parent
        text: "Push"
        onClicked:  stackView.push(redRect)
    }
    Rectangle { id: redRect; color: "red" }
}