Attached properties of items exposed from a component do not work in property view

import QtQuick

Item {
    id: _item
    width: 200
    height: 200

    property alias text: _text
    property alias background: _rectangle

    Rectangle {
        id: _rectangle
        anchors.fill: parent
        color: "#ffffff"
        Text {
            id: _text
            x: 276
            y: 100
            text: qsTr("Hello")
            anchors.verticalCenter: parent.verticalCenter
            anchors.horizontalCenter: parent.horizontalCenter

            font.family: Constants.font.family
        }
    }
}