TextInput selectWord() on word's first letter often selects two words

import Qt 4.7

Item
{
    width: 600
    height: 400

    Rectangle {
        width: 400
        height: 40
        color: "lightgreen"
        anchors.centerIn: parent

        TextInput {
            id: textInput
            anchors.fill: parent
            text: "This is a TextInput text"
            font.pixelSize: 30
            selectByMouse: true

            MouseArea {
                anchors.fill: parent
                onPressed: {
                    print("pressed")
                    textInput.focus = true;
                    textInput.cursorPosition = textInput.positionAt(mouse.x);
                }

                onDoubleClicked: {
                    print("double-clicked")
                    textInput.selectWord(textInput.positionAt(mouse.x));
                }
            }
        }
    }
}