diff -r 41300fa6a67c -r 2f34d5167611 src/gui/kernel/qwidget_mac.mm
--- a/src/gui/kernel/qwidget_mac.mm	Tue Feb 02 00:43:10 2010 +0200
+++ b/src/gui/kernel/qwidget_mac.mm	Fri Apr 16 15:50:13 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)
 **
@@ -110,6 +110,7 @@
 #include "qevent_p.h"
 #include "qdnd_p.h"
 #include <QtGui/qgraphicsproxywidget.h>
+#include "qmainwindow.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -403,7 +404,7 @@
         return;
     qt_mac_app_fullscreen = b;
     if (b) {
-        SetSystemUIMode(kUIModeAllSuppressed, 0);
+        SetSystemUIMode(kUIModeAllHidden, kUIOptionAutoShowMenuBar);
     } else {
         SetSystemUIMode(kUIModeNormal, 0);
     }
@@ -564,6 +565,25 @@
 }
 #endif
 
+#ifdef QT_MAC_USE_COCOA
+void qt_mac_set_needs_display(QWidget *widget, QRegion region)
+{
+    NSView *theNSView = qt_mac_nativeview_for(widget);
+    if (region.isEmpty()) {
+        [theNSView setNeedsDisplay:YES];
+        return;
+    }
+
+    QVector<QRect> rects = region.rects();
+    for (int i = 0; i<rects.count(); ++i) {
+        const QRect &rect = rects.at(i);
+        NSRect nsrect = NSMakeRect(rect.x(), rect.y(), rect.width(), rect.height());
+        [theNSView setNeedsDisplayInRect:nsrect];
+    }
+
+}
+#endif
+
 inline static bool updateRedirectedToGraphicsProxyWidget(QWidget *widget, const QRect &rect)
 {
     if (!widget)
@@ -1721,6 +1741,15 @@
 void QWidgetPrivate::determineWindowClass()
 {
     Q_Q(QWidget);
+#if !defined(QT_NO_MAINWINDOW) && !defined(QT_NO_TOOLBAR)
+    // Make sure that QMainWindow has the MacWindowToolBarButtonHint when the
+    // unifiedTitleAndToolBarOnMac property is ON. This is to avoid reentry of
+    // setParent() triggered by the QToolBar::event(QEvent::ParentChange).
+    QMainWindow *mainWindow = qobject_cast<QMainWindow *>(q);
+    if (mainWindow && mainWindow->unifiedTitleAndToolBarOnMac()) {
+        data.window_flags |= Qt::MacWindowToolBarButtonHint;
+    }
+#endif
 #ifndef QT_MAC_USE_COCOA
 // ### COCOA:Interleave these better!
 
@@ -2743,7 +2772,9 @@
         }
         if (wasWindow) {
             oldToolbar = [oldWindow toolbar];
+            [oldToolbar retain];
             oldToolbarVisible = [oldToolbar isVisible];
+            [oldWindow setToolbar:nil];
         }
 #endif
     }
@@ -2787,6 +2818,7 @@
             if (oldToolbar && !(f & Qt::FramelessWindowHint)) {
                 OSWindowRef newWindow = qt_mac_window_for(q);
                 [newWindow setToolbar:oldToolbar];
+                [oldToolbar release];
                 [oldToolbar setVisible:oldToolbarVisible];
             }
 #endif
@@ -3401,6 +3433,38 @@
             ShowHide(window, false);
 #else
             [window orderOut:window];
+            // Unfortunately it is not as easy as just hiding the window, we need
+            // to find out if we were in full screen mode. If we were and this is
+            // the last window in full screen mode then we need to unset the full screen
+            // mode. If this is not the last visible window in full screen mode then we
+            // don't change the full screen mode.
+            if(q->isFullScreen())
+            {
+                bool keepFullScreen = false;
+                QWidgetList windowList = qApp->topLevelWidgets();
+                int windowCount = windowList.count();
+                for(int i = 0; i < windowCount; i++)
+                {
+                    QWidget *w = windowList[i];
+                    // If it is the same window, we don't need to check :-)
+                    if(q == w)
+                        continue;
+                    // If they are not visible or if they are minimized then
+                    // we just ignore them.
+                    if(!w->isVisible() || w->isMinimized())
+                        continue;
+                    // Is it full screen?
+                    // Notice that if there is one window in full screen mode then we
+                    // cannot switch the full screen mode off, therefore we just abort.
+                    if(w->isFullScreen()) {
+                        keepFullScreen = true;
+                        break;
+                    }
+                }
+                // No windows in full screen mode, so let just unset that flag.
+                if(!keepFullScreen)
+                    qt_mac_set_fullscreen_mode(false);
+            }
 #endif
             toggleDrawers(false);
 #ifndef QT_MAC_USE_COCOA
@@ -3465,6 +3529,8 @@
 
     if (!QWidget::mouseGrabber()){
         QWidget *enterWidget = QApplication::widgetAt(QCursor::pos());
+        if (enterWidget && enterWidget->data->in_destructor)
+            enterWidget = 0;
         QApplicationPrivate::dispatchEnterLeave(enterWidget, qt_mouseover);
         qt_mouseover = enterWidget;
     }
@@ -3671,6 +3737,7 @@
         return;
 
 #if QT_MAC_USE_COCOA
+    QMacCocoaAutoReleasePool pool;
     if (isRealWindow()) {
         // Calling orderFront shows the window on Cocoa too.
         if (!q->testAttribute(Qt::WA_DontShowOnScreen) && q->isVisible()) {
@@ -4493,10 +4560,14 @@
 void QWidgetPrivate::deleteTLSysExtra()
 {
 #ifndef QT_MAC_USE_COCOA
-    if(extra->topextra->group) {
+    if (extra->topextra->group) {
         qt_mac_release_window_group(extra->topextra->group);
         extra->topextra->group = 0;
     }
+    if (extra->topextra->windowIcon) {
+        ReleaseIconRef(extra->topextra->windowIcon);
+        extra->topextra->windowIcon = 0;
+    }
 #endif
 }