Prevent QDialog/QWidget from moving - bool QWidget::nativeEvent

[hbatalha]

I want to know how I can prevent a window from being moved around using the titlebar.
I know I can set the flag to Qt::FramelessWindowHint but I need to have the titlebar.

Someone is this topic claimed he did it using bool nativeEvent(const QByteArray &eventType, void *message, long *result) but never shared how he exactly he did that.