Strange "incomplete type" error in QGraphicsItem

Possible duplicate:
What leads to incomplete types? (QGraphicsItem: source or target is of an incomplete type)

I started with this question: What leads to incomplete types? (QGraphicsItem: source or target is of an incomplete type)

As already mentioned, I got the following error (partially my own translation):

C664: Converting parameter 1 from 'Qt :: CursorShape' to 'const QCursor &' is not possible. The source or target is of an incomplete type.

When trying to figure out why the item may be incomplete, I split it into a minimal test case that still shows an error. Strange: this is absolutely minimal ...

Title:

#include <QGraphicsPixmapItem>

class PhotoItem : public QGraphicsPixmapItem
{
public:
    PhotoItem();
    void someMethod();

protected:
};

Implementation:

#include "photoitem.h"

PhotoItem::PhotoItem() : QGraphicsPixmapItem()
{
    QPixmap pxm(80, 80);
    pxm.fill(Qt::cyan);
    setPixmap( pxm );
}

void PhotoItem::someMethod()
{
    setCursor(Qt::OpenHandCursor);
}

, , . item->setCursor(Qt::OpenHandCursor); . , -, QGraphicsItems ( , QGraphicsRectItem).

, . /? , ?

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