diff -r dee5afe5301f -r 3f74d0d4af4c src/gui/graphicsview/qgraphicssceneindex.cpp
--- a/src/gui/graphicsview/qgraphicssceneindex.cpp	Mon Mar 15 12:43:09 2010 +0200
+++ b/src/gui/graphicsview/qgraphicssceneindex.cpp	Thu Apr 08 14:19:33 2010 +0300
@@ -279,7 +279,7 @@
         return;
 
     const qreal opacity = item->d_ptr->combineOpacityFromParent(parentOpacity);
-    const bool itemIsFullyTransparent = (opacity < 0.0001);
+    const bool itemIsFullyTransparent = QGraphicsItemPrivate::isOpacityNull(opacity);
     const bool itemHasChildren = !item->d_ptr->children.isEmpty();
     if (itemIsFullyTransparent && (!itemHasChildren || item->d_ptr->childrenCombineOpacity()))
         return;
@@ -554,7 +554,7 @@
 
 /*!
     \fn QList<QGraphicsItem *> QGraphicsSceneIndex::items(Qt::SortOrder order = Qt::DescendingOrder) const
-    
+
     This pure virtual function all items in the index and sort them using
     \a order.
 */