Example 2 (tunneling)

import QtQuick 2.5
import QtQuick.Window 2.2
import QtQuick.Controls 1.4

Window {
    visible: true
    width: 640
    height: 480
    title: qsTr("Hello World")

    ComboBox {
        focus: true
        activeFocusOnPress: true
        model: 2
        Keys.onPressedPreview: event.accepted = true
    }
}