QWebEngineView::{dragEnter/dragLeave/dragMove/drop}Event not called

In kmail I need to intercept dnd action.
But even if I reimplement
" void dragEnterEvent(QDragEnterEvent *e) Q_DECL_OVERRIDE;
void dragLeaveEvent(QDragLeaveEvent *e) Q_DECL_OVERRIDE;
void dragMoveEvent(QDragMoveEvent *e) Q_DECL_OVERRIDE;
void dropEvent(QDropEvent *e) Q_DECL_OVERRIDE;
"
I can't have access to it.
I added debug but I didn't see method.

There is a problem ? or I missed something ?

I create a test case I attach it.

Thanks