QGraphicsView repainting item problem with ScrollBar

[Grade]

Hi everyone.
I'm currently making a Map Editor with Qt, and I have a problem I don't understand.
I have a QGraphicsView which draws my tileset and I can select one/multiple tiles by clicking them (If I hold the clic I can select several tiles at one time). It works fine but here's my problem: My QGraphicsView has a verticalScrollBar, and when I scroll over/under the cursor, the cursor gets cut (not everytime though), but it's always the bottom part of the cursor that gets cut.

Here the code of my cursor (it's a custom QGraphicsItem) :

cursoritem.h

#ifndef CURSORITEM_H
#define CURSORITEM_H
 
#include <QGraphicsItem>
 
class Fenetre;
 
class CursorItem : public QGraphicsItem
{
public:
    CursorItem(Fenetre* parent=0);
    QRectF boundingRect() const;
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
               QWidget *widget);
    void setX(int i);
    void setY(int i);
    void setW(int i);
    void setH(int i);
 
private:
    Fenetre* fenetre;
    int x;
    int y;
    int w;
    int h;
 
};
 
#endif // CURSORITEM_H

#ifndef CURSORITEM_H
#define CURSORITEM_H

#include <QGraphicsItem>

class Fenetre;

class CursorItem : public QGraphicsItem
{
public:
    CursorItem(Fenetre* parent=0);
    QRectF boundingRect() const;
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
               QWidget *widget);
    void setX(int i);
    void setY(int i);
    void setW(int i);
    void setH(int i);

private:
    Fenetre* fenetre;
    int x;
    int y;
    int w;
    int h;

};

#endif // CURSORITEM_H

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cursoritem.cpp

#include <QGraphicsSceneMouseEvent>
#include <QPainter>
#include <QPixmap>
#include <QMessageBox>
#include "cursoritem.h"
#include "fenetre.h"
 
CursorItem::CursorItem(Fenetre *parent) :
    QGraphicsItem(), fenetre(parent), x(0),y(0),w(1),h(1)
{
}
 
QRectF CursorItem::boundingRect() const
{
    return QRectF(0, 0,
                  w*32, h*32);
}
 
void CursorItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
    painter->drawRect(0,0,w*32,h*32);
}
 
void CursorItem::setX(int i)
    { x=i; }
 
void CursorItem::setY(int i)
    { y=i; }
 
void CursorItem::setW(int i)
    { w=i; }
 
void CursorItem::setH(int i)
    { h=i; }

#include <QGraphicsSceneMouseEvent>
#include <QPainter>
#include <QPixmap>
#include <QMessageBox>
#include "cursoritem.h"
#include "fenetre.h"

CursorItem::CursorItem(Fenetre *parent) :
    QGraphicsItem(), fenetre(parent), x(0),y(0),w(1),h(1)
{
}

QRectF CursorItem::boundingRect() const
{
    return QRectF(0, 0,
                  w*32, h*32);
}

void CursorItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
    painter->drawRect(0,0,w*32,h*32);
}

void CursorItem::setX(int i)
    { x=i; }

void CursorItem::setY(int i)
    { y=i; }

void CursorItem::setW(int i)
    { w=i; }

void CursorItem::setH(int i)
    { h=i; }

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If you need anymore details just ask. I'd really appreciate if someone could help me.
Thanks!

[Grade]

Fixed.
I just needed to use QGraphicsItem::prepareGeometryChange() to tell that the cursor's BoundingRect has changed.