In http://doc.trolltech.com/4.6/qgraphicsitem.html#GraphicsItemChange-enum you can read

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enum QGraphicsItem::GraphicsItemChange

ItemVisibleHasChanged, ItemEnabledHasChanged, ItemSelectedHasChanged, ItemParentHasChanged, ItemSceneHasChanged

This enum describes the state changes that are notified by QGraphicsItem::itemChange(). The notifications are sent as the state changes, and in some cases, adjustments can be made (see the documentation for each change for details).
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I think the "ItemVisibleHasChanged, ItemEnabledHasChanged, ItemSelectedHasChanged, ItemParentHasChanged, ItemSceneHasChanged" do not make any sense there.