The activeFocusChanged signal not emitted when QML Viewer window itself has no focus.

import QtQuick 1.1

Rectangle {
    width: 120
    height: 120
    color: activeFocus ? "blue" : "red"
    Text {
        anchors.centerIn: parent
        text: "Text"
    }
    MouseArea {
        anchors.fill: parent
        onClicked: {
            parent.forceActiveFocus()
        }
    }
}