1 files changed, 32 insertions, 15 deletions

diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index ff46e2e..a9578f2 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -616,6 +616,30 @@ void QGraphicsScenePrivate::_q_emitUpdated()
 
 /*!
     \internal
+*/
+void QGraphicsScenePrivate::registerTopLevelItem(QGraphicsItem *item)
+{
+    item->d_ptr->siblingIndex = topLevelItems.size();
+    topLevelItems.append(item);
+}
+
+/*!
+    \internal
+*/
+void QGraphicsScenePrivate::unregisterTopLevelItem(QGraphicsItem *item)
+{
+    int idx = item->d_ptr->siblingIndex;
+    int size = topLevelItems.size();
+    for (int i = idx; i < size - 1; ++i) {
+        QGraphicsItem *p = topLevelItems[i + 1];
+        topLevelItems[i] = p;
+        p->d_ptr->siblingIndex = i;
+    }
+    topLevelItems.removeLast();
+}
+
+/*!
+    \internal
 
     Updates all items in the pending update list. At this point, the list is
     unlikely to contain partially constructed items.
@@ -690,13 +714,6 @@ void QGraphicsScenePrivate::_q_removeItemLater(QGraphicsItem *item)
 {
     Q_Q(QGraphicsScene);
 
-    if (QGraphicsItem *parent = item->d_func()->parent) {
-        QVariant variant;
-        qVariantSetValue<QGraphicsItem *>(variant, item);
-        parent->itemChange(QGraphicsItem::ItemChildRemovedChange, variant);
-        parent->d_func()->children.removeAll(item);
-    }
-
     // Clear focus on the item to remove any reference in the focusWidget
     // chain.
     item->clearFocus();
@@ -747,10 +764,6 @@ void QGraphicsScenePrivate::_q_removeItemLater(QGraphicsItem *item)
         freeSceneTransformSlots.append(transformIndex);
     }
 
-    // Remove all children recursively.
-    foreach (QGraphicsItem *child, item->children())
-        _q_removeItemLater(child);
-
     // Reset the mouse grabber
     if (mouseGrabberItems.contains(item))
         ungrabMouse(item, /* item is dying */ true);
@@ -1682,7 +1695,7 @@ inline bool qt_closestLeaf(const QGraphicsItem *item1, const QGraphicsItem *item
     if (f1 != f2) return f2;
     qreal z1 = d1->z;
     qreal z2 = d2->z;
-    return z1 != z2 ? z1 > z2 : item1 > item2;
+    return z1 != z2 ? z1 > z2 : d1->siblingIndex > d2->siblingIndex;
 }
 
 /*!
@@ -2607,7 +2620,6 @@ void QGraphicsScene::clear()
     }
     d->unindexedItems.clear();
     qDeleteAll(unindexedParents);
-
     d->indexedItems.clear();
     d->freeItemIndexes.clear();
     d->lastItemCount = 0;
@@ -2716,7 +2728,6 @@ void QGraphicsScene::addItem(QGraphicsItem *item)
         qWarning("QGraphicsScene::addItem: item has already been added to this scene");
         return;
     }
-
     // Remove this item from its existing scene
     if (QGraphicsScene *oldScene = item->scene())
         oldScene->removeItem(item);
@@ -2756,6 +2767,10 @@ void QGraphicsScene::addItem(QGraphicsItem *item)
     item->d_func()->index = -1;
     d->startIndexTimer();
 
+    // Add to list of toplevels if this item is a toplevel.
+    if (!item->d_ptr->parent)
+        d->registerTopLevelItem(item);
+
     // Update the scene's sort cache settings.
     item->d_ptr->globalStackingOrder = -1;
     d->invalidateSortCache();
@@ -3107,13 +3122,15 @@ void QGraphicsScene::removeItem(QGraphicsItem *item)
     // Set the item's scene ptr to 0.
     item->d_func()->scene = 0;
 
-    // Detach the item from its parent.
+    // Remove from parent, or unregister from toplevels.
     if (QGraphicsItem *parentItem = item->parentItem()) {
         if (parentItem->scene()) {
             Q_ASSERT_X(parentItem->scene() == this, "QGraphicsScene::removeItem",
                        "Parent item's scene is different from this item's scene");
             item->setParentItem(0);
         }
+    } else {
+        d->unregisterTopLevelItem(item);
     }
 
     // Remove from our item lists.