Error of the possibleActions value of the drag event

QDrag *drag = new QDrag(button);        

drag->setMimeData(new QMimeData());
drag->exec(Qt::MoveAction | Qt::CopyAction, Qt::CopyAction);

void MainWindow::dragEnterEvent(QDragEnterEvent *event)
{
    qDebug() << event->proposedAction() << event->possibleActions();
}