QGraphicsItem doesn't update

[Vyivrain]

Hello , I have a problem, that QGraphicsItem doesn't update, when I'm calling update(). This is what I'm doing:
CircleItem.cpp

void CircleItem::mouseMoveEvent(QGraphicsSceneMouseEven t *event)
{
RectItem->SetBackGround();
QGraphicsItem::mouseMoveEvent( event );
}

RoundRectItem.cpp

void RoundRectItem::SetBackGround()
{
ChangeBackground = true;
update();
}

void RoundRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
QRectF rec = QRectF( QPoint( 0,0 ), boundingRect().size() / 2 );

roundRect = QRectF(rec.adjusted(-rec.height() / 2, 0, rec.height()/2, 0));

roundRect.moveTo( boundingRect().center().x() - roundRect.width() / 2,
boundingRect().center().y() - roundRect.height() / 2 );

if( !ChangeBackground )
painter->setBrush( backBrush );
else
painter->setBrush( QBrush( Qt::blue ) );

painter->setPen( QColor( 255,255,255 ) );

painter->drawRoundedRect(roundRect, roundRect.height() / 2, roundRect.height() / 2 );

}
And after this, roundrect doesn't update its background.