DropShadow no longer works in layer

import QtQuick 2.5
import QtQuick.Window 2.2
import QtGraphicalEffects 1.0

Window {
    width: 200
    height: 200
    visible: true

    Rectangle {
        width: 50
        height: 50
        radius: 5
        color: "tomato"
        anchors.centerIn: parent

        layer.enabled: true
        layer.effect: DropShadow {
            verticalOffset: 3
            horizontalOffset: 3
            color: "gray"
            spread: 0.5
            samples: 15
        }
    }
}