Disable view move when dragging mouse in QGraphicsView

Hello all,
I want QGraphicsView to stay still when I keep click pressed and move mouse, so there would be no move of the view.

So far, I've done this

- setDragMode(QGraphicsView::NoDrag);
- protected: virtual void dragMoveEvent(QDragMoveEvent *event) override; defined empty
- protected: virtual void scrollContentsBy(int dx, int dy) override; defined empty
- protected: virtual void dragMoveEvent(QGraphicsSceneDragDropEvent *event) override; defined empty for my QGraphicsScene

But I still have this :

https://i.stack.imgur.com/ftCe5.gif