diff -r 41300fa6a67c -r f7bc934e204c src/gui/widgets/qmainwindowlayout_mac.mm
--- a/src/gui/widgets/qmainwindowlayout_mac.mm	Tue Feb 02 00:43:10 2010 +0200
+++ b/src/gui/widgets/qmainwindowlayout_mac.mm	Wed Mar 31 11:06:36 2010 +0300
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
@@ -463,6 +463,8 @@
             NSToolbarItem *item = static_cast<NSToolbarItem *>(it.key());
             [[qt_mac_window_for(layoutState.mainWindow->window()) toolbar]
                 removeItemAtIndex:toolbarItemsCopy.indexOf(item)];
+             unifiedToolbarHash.remove(item);
+             qtoolbarsInUnifiedToolbarList.removeAll(toolbar);
 #endif
             break;
         }
@@ -472,10 +474,27 @@
 
 void QMainWindowLayout::cleanUpMacToolbarItems()
 {
-    for (int i = 0; i < toolbarItemsCopy.size(); ++i)
+#ifdef QT_MAC_USE_COCOA
+    QMacCocoaAutoReleasePool pool;
+#endif
+    for (int i = 0; i < toolbarItemsCopy.size(); ++i) {
+#ifdef QT_MAC_USE_COCOA
+        NSToolbarItem *item = static_cast<NSToolbarItem *>(toolbarItemsCopy.at(i));
+        [item setView:0];
+#endif
         CFRelease(toolbarItemsCopy.at(i));
+    }
     toolbarItemsCopy.clear();
     unifiedToolbarHash.clear();
+
+#ifdef QT_MAC_USE_COCOA
+    OSWindowRef window = qt_mac_window_for(layoutState.mainWindow);
+    NSToolbar *macToolbar = [window toolbar];
+    if (macToolbar) {
+      [[macToolbar delegate] release];
+      [macToolbar setDelegate:nil];
+    }
+#endif
 }
 
 void QMainWindowLayout::fixSizeInUnifiedToolbar(QToolBar *tb) const