Pre-edit text is not displayed in TextEdit element

Test the following application:

import QtQuick 2.0

Rectangle {
    width: 640
    height: 480

    TextEdit {
        anchors.centerIn: parent
        width: parent.width
    }
}

Select an input method with pre-edit features, and input some text. Regardless of the contents in the input field, the pre-edit text will not be displayed.