[regression] javascript array binding not working

import QtQuick 2.2
import QtQuick.Controls 1.0
import QtQuick.Window 2.1
import GSettings 1.0

Window {
    id:window;
    title:qsTr("TEST")
    width:640 ;height:480;
    color:"black"
    MouseArea{anchors.fill: parent;onClicked: window.testCase()}

function testCase()
{
    var a = test.activePlugins
      a.push('vier')
    test.activePlugins = a

    console.log(a)
    console.log(test.activePlugins)
}
    GSettings {id:test;
        schema.id:"org.gnome.gedit.plugins";
        schema.path:"/org/gnome/gedit/plugins/";
    }

}