int main( int argc, char **argv)
{
    QApplication a(argc, argv);

    QWidget w;
    w.setWindowFlags(Qt::Window | Qt::FramelessWindowHint | Qt::WindowStaysOnTopHint | Qt::ToolTip);
    w.setFocusPolicy(Qt::WheelFocus);
    w.setMouseTracking(true);
    w.setCursor(Qt::CrossCursor); // Cursor is not changed
    w.setFixedSize(200, 200);
    w.move(200, 200);
    w.show();

    return a.exec();
}