diff --git a/src/plugins/platforms/cocoa/qcocoawindow.h b/src/plugins/platforms/cocoa/qcocoawindow.h
index 256f5ee6fb..748280af6a 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.h
+++ b/src/plugins/platforms/cocoa/qcocoawindow.h
@@ -52,32 +52,42 @@
 
 QT_FORWARD_DECLARE_CLASS(QCocoaWindow)
 
-@class QNSWindowDelegate;
-
-@interface QNSWindow : NSPanel {
-@public
-   QCocoaWindow *m_cocoaPlatformWindow;
+@interface QNSWindow : NSWindow
+{
+    @public QCocoaWindow *m_cocoaPlatformWindow;
 }
+- (id)initWithContentRect:(NSRect)contentRect
+      styleMask:(NSUInteger)windowStyle
+      qPlatformWindow:(QCocoaWindow *)qpw;
 
 - (void)clearPlatformWindow;
 @end
 
-QT_BEGIN_NAMESPACE
+@interface QNSPanel : NSPanel
+{
+    @public QCocoaWindow *m_cocoaPlatformWindow;
+}
 
+- (id)initWithContentRect:(NSRect)contentRect
+      styleMask:(NSUInteger)windowStyle
+      qPlatformWindow:(QCocoaWindow *)qpw;
+
+- (void)clearPlatformWindow;
+@end
+
+@class QNSWindowDelegate;
+
+QT_BEGIN_NAMESPACE
 // QCocoaWindow
 //
-// A QCocoaWindow is backed by a NSView and optionally a NSWindow.
+// QCocoaWindow is an NSView (not an NSWindow!) in the sense
+// that it relies on a NSView for all event handling and
+// graphics output and does not require a NSWindow, except for
+// for the window-related functions like setWindowTitle.
 //
-// The NSView is used for most event handling and graphics output.
-//
-// Top-level QWindows are always backed by a NSWindow in addition to
-// the NSView. Child QWindows can also be backed by NSWindows, which
-// enables proper stacking of GL Widgets and threaded GL rendering
-// to multiple contexts.
-//
-// It is possible to embed the QCocoaWindow in an NSView hierarchy
-// by getting a pointer to the backing NSView and not calling
-// QCocoaWindow::show():
+// As a consequence of this it is possible to embed the QCocoaWindow
+// in an NSView hierarchy by getting a pointer to the "backing"
+// NSView and not calling QCocoaWindow::show():
 //
 // QWindow *qtWindow = new MyWindow();
 // qtWindow->create();
@@ -139,7 +149,6 @@ public:
     void windowDidResize();
     bool windowShouldClose();
     bool windowIsPopupType(Qt::WindowType type = Qt::Widget) const;
-    bool windowShouldBehaveAsPanel() const;
 
     void setSynchedWindowStateFromWindow();
 
@@ -174,9 +183,11 @@ public:
     QWindow *childWindowAt(QPoint windowPoint);
 protected:
     void recreateWindow(const QPlatformWindow *parentWindow);
-    QNSWindow *createNSWindow();
-    void setNSWindow(QNSWindow *window);
-    void clearNSWindow(QNSWindow *window);
+    NSWindow *createNSWindow();
+    void setNSWindow(NSWindow *window);
+    void clearNSWindow(NSWindow *window);
+
+    bool shouldUseNSPanel();
 
     QRect windowGeometry() const;
     QCocoaWindow *parentCocoaWindow() const;
@@ -191,7 +202,7 @@ public: // for QNSView
 
     NSView *m_contentView;
     QNSView *m_qtView;
-    QNSWindow *m_nsWindow;
+    NSWindow *m_nsWindow;
     QCocoaWindow *m_forwardWindow;
 
     // TODO merge to one variable if possible
diff --git a/src/plugins/platforms/cocoa/qcocoawindow.mm b/src/plugins/platforms/cocoa/qcocoawindow.mm
index d71fe1ee18..d972782f31 100644
--- a/src/plugins/platforms/cocoa/qcocoawindow.mm
+++ b/src/plugins/platforms/cocoa/qcocoawindow.mm
@@ -81,10 +81,15 @@ static bool isMouseEvent(NSEvent *ev)
 }
 
 @interface NSWindow (CocoaWindowCategory)
+- (void) clearPlatformWindow;
 - (NSRect) legacyConvertRectFromScreen:(NSRect) rect;
 @end
 
 @implementation NSWindow (CocoaWindowCategory)
+- (void) clearPlatformWindow
+{
+}
+
 - (NSRect) legacyConvertRectFromScreen:(NSRect) rect
 {
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
@@ -123,17 +128,9 @@ static bool isMouseEvent(NSEvent *ev)
     if (!m_cocoaPlatformWindow || m_cocoaPlatformWindow->m_isNSWindowChild)
         return NO;
 
-    // Only tool or dialog windows should become key:
-    if (m_cocoaPlatformWindow && m_cocoaPlatformWindow->windowShouldBehaveAsPanel()) {
-        Qt::WindowType type = m_cocoaPlatformWindow->window()->type();
-        if (type == Qt::Tool || type == Qt::Dialog)
-            return YES;
-        return NO;
-    }
-
-    // All other windows can become the key window. This includes
-    // popup windows such as the combobox popup, which is a title-bar
-    // less window that by default can't become key.
+    // The default implementation returns NO for title-bar less windows,
+    // override and return yes here to make sure popup windows such as
+    // the combobox popup can become the key window.
     return YES;
 }
 
@@ -147,9 +144,6 @@ static bool isMouseEvent(NSEvent *ev)
         || m_cocoaPlatformWindow->window()->transientParent())
         canBecomeMain = NO;
 
-    if (m_cocoaPlatformWindow && m_cocoaPlatformWindow->windowShouldBehaveAsPanel())
-        canBecomeMain = NO;
-
     return canBecomeMain;
 }
 
@@ -198,6 +192,64 @@ static bool isMouseEvent(NSEvent *ev)
 
 @end
 
+@implementation QNSPanel
+
+- (id)initWithContentRect:(NSRect)contentRect
+      styleMask:(NSUInteger)windowStyle
+      qPlatformWindow:(QCocoaWindow *)qpw
+{
+    self = [super initWithContentRect:contentRect
+            styleMask:windowStyle
+            backing:NSBackingStoreBuffered
+            defer:NO]; // Deferring window creation breaks OpenGL (the GL context is
+                       // set up before the window is shown and needs a proper window)
+
+    if (self) {
+        m_cocoaPlatformWindow = qpw;
+    }
+    return self;
+}
+
+- (BOOL)canBecomeKeyWindow
+{
+    if (!m_cocoaPlatformWindow)
+        return NO;
+
+    // Only tool or dialog windows should become key:
+    if (m_cocoaPlatformWindow
+        && (m_cocoaPlatformWindow->window()->type() == Qt::Tool ||
+            m_cocoaPlatformWindow->window()->type() == Qt::Dialog))
+        return YES;
+    return NO;
+}
+
+- (void) sendEvent: (NSEvent*) theEvent
+{
+    [super sendEvent: theEvent];
+
+    if (!m_cocoaPlatformWindow)
+        return;
+
+    if (m_cocoaPlatformWindow->frameStrutEventsEnabled() && isMouseEvent(theEvent)) {
+        NSPoint loc = [theEvent locationInWindow];
+        NSRect windowFrame = [self legacyConvertRectFromScreen:[self frame]];
+        NSRect contentFrame = [[self contentView] frame];
+        if (NSMouseInRect(loc, windowFrame, NO) &&
+            !NSMouseInRect(loc, contentFrame, NO))
+        {
+            QNSView *contentView = (QNSView *) m_cocoaPlatformWindow->contentView();
+            [contentView handleFrameStrutMouseEvent: theEvent];
+        }
+    }
+}
+
+- (void)clearPlatformWindow
+{
+    m_cocoaPlatformWindow = 0;
+}
+
+@end
+
 const int QCocoaWindow::NoAlertRequest = -1;
 
 QCocoaWindow::QCocoaWindow(QWindow *tlw)
@@ -675,21 +727,15 @@ void QCocoaWindow::setWindowFlags(Qt::WindowFlags flags)
 
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
         if (QSysInfo::QSysInfo::MacintoshVersion >= QSysInfo::MV_10_7) {
-            NSWindowCollectionBehavior behavior = [m_nsWindow collectionBehavior];
-            if (windowShouldBehaveAsPanel()) {
-                behavior &= ~NSWindowCollectionBehaviorFullScreenPrimary;
-                behavior |= NSWindowCollectionBehaviorFullScreenAuxiliary;
-            } else {
+            Qt::WindowType type = window()->type();
+            if ((type & Qt::Popup) != Qt::Popup && (type & Qt::Dialog) != Qt::Dialog) {
+                NSWindowCollectionBehavior behavior = [m_nsWindow collectionBehavior];
                 if (flags & Qt::WindowFullscreenButtonHint)
                     behavior |= NSWindowCollectionBehaviorFullScreenPrimary;
                 else
                     behavior &= ~NSWindowCollectionBehaviorFullScreenPrimary;
+                [m_nsWindow setCollectionBehavior:behavior];
             }
-            [m_nsWindow setCollectionBehavior:behavior];
-
-            [m_nsWindow setAnimationBehavior:(flags & Qt::Popup) == Qt::Popup
-                                             ? NSWindowAnimationBehaviorUtilityWindow
-                                             : NSWindowAnimationBehaviorDefault];
         }
 #endif
     }
@@ -1013,14 +1059,6 @@ bool QCocoaWindow::windowIsPopupType(Qt::WindowType type) const
     return ((type & Qt::Popup) == Qt::Popup);
 }
 
-bool QCocoaWindow::windowShouldBehaveAsPanel() const
-{
-    // Before merging QNSPanel and QNSWindow, we used NSPanel for popup-type
-    // windows (Popup, Tool, ToolTip, SplashScreen) and dialogs
-    Qt::WindowType type = window()->type();
-    return (type & Qt::Popup) == Qt::Popup || (type & Qt::Dialog) == Qt::Dialog;
-}
-
 void QCocoaWindow::setCurrentContext(QCocoaGLContext *context)
 {
     m_glContext = context;
@@ -1034,17 +1072,21 @@ QCocoaGLContext *QCocoaWindow::currentContext() const
 void QCocoaWindow::recreateWindow(const QPlatformWindow *parentWindow)
 {
     bool wasNSWindowChild = m_isNSWindowChild;
+    // TODO Set value for m_isNSWindowChild here
     bool needsNSWindow = m_isNSWindowChild || !parentWindow;
 
     QCocoaWindow *oldParentCocoaWindow = m_parentCocoaWindow;
     m_parentCocoaWindow = const_cast<QCocoaWindow *>(static_cast<const QCocoaWindow *>(parentWindow));
 
+    bool usesNSPanel = [m_nsWindow isKindOfClass:[QNSPanel class]];
+
     // No child QNSWindow should notify its QNSView
     if (m_nsWindow && m_qtView && m_parentCocoaWindow && !oldParentCocoaWindow)
         [[NSNotificationCenter defaultCenter] removeObserver:m_qtView
                                               name:nil object:m_nsWindow];
+
     // Remove current window (if any)
-    if (m_nsWindow && !needsNSWindow) {
+    if ((m_nsWindow && !needsNSWindow) || (usesNSPanel != shouldUseNSPanel())) {
         clearNSWindow(m_nsWindow);
         [m_nsWindow close];
         [m_nsWindow release];
@@ -1075,7 +1117,6 @@ void QCocoaWindow::recreateWindow(const QPlatformWindow *parentWindow)
         setNSWindow(m_nsWindow);
     }
 
-
     if (m_contentViewIsToBeEmbedded) {
         // An embedded window doesn't have its own NSWindow.
     } else if (!parentWindow) {
@@ -1147,13 +1188,22 @@ void QCocoaWindow::requestActivateWindow()
     [ window makeKeyWindow ];
 }
 
-QNSWindow * QCocoaWindow::createNSWindow()
+bool QCocoaWindow::shouldUseNSPanel()
+{
+    Qt::WindowType type = window()->type();
+
+    return !m_isNSWindowChild &&
+           ((type & Qt::Popup) == Qt::Popup || (type & Qt::Dialog) == Qt::Dialog);
+}
+
+NSWindow * QCocoaWindow::createNSWindow()
 {
     QCocoaAutoReleasePool pool;
 
     QRect rect = initialGeometry(window(), window()->geometry(), defaultWindowWidth, defaultWindowHeight);
     NSRect frame = qt_mac_flipRect(rect, window());
 
+    Qt::WindowType type = window()->type();
     Qt::WindowFlags flags = window()->flags();
 
     NSUInteger styleMask;
@@ -1162,17 +1212,44 @@ QNSWindow * QCocoaWindow::createNSWindow()
     } else {
         styleMask = windowStyleMask(flags);
     }
+    NSWindow *createdWindow = 0;
 
-    QNSWindow *createdWindow = [[QNSWindow alloc] initWithContentRect:frame styleMask:styleMask qPlatformWindow:this];
-
-    Qt::WindowFlags type = window()->type();
-    createdWindow.hidesOnDeactivate = type == Qt::Tool || type == Qt::ToolTip;
+    // Use NSPanel for popup-type windows. (Popup, Tool, ToolTip, SplashScreen)
+    // and dialogs
+    if (shouldUseNSPanel()) {
+        QNSPanel *window;
+        window  = [[QNSPanel alloc] initWithContentRect:frame
+                                    styleMask: styleMask
+                                    qPlatformWindow:this];
+        if ((type & Qt::Popup) == Qt::Popup)
+            [window setHasShadow:YES];
+        [window setHidesOnDeactivate: NO];
 
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
-    if (QSysInfo::QSysInfo::MacintoshVersion >= QSysInfo::MV_10_7) {
-        [createdWindow setRestorable: NO];
-    }
+        if (QSysInfo::QSysInfo::MacintoshVersion >= QSysInfo::MV_10_7) {
+            // Make popup winows show on the same desktop as the parent full-screen window.
+            [window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenAuxiliary];
+
+            if ((type & Qt::Popup) == Qt::Popup)
+                [window setAnimationBehavior:NSWindowAnimationBehaviorUtilityWindow];
+        }
 #endif
+        createdWindow = window;
+    } else {
+        QNSWindow *window;
+        window  = [[QNSWindow alloc] initWithContentRect:frame
+                                     styleMask: styleMask
+                                     qPlatformWindow:this];
+        createdWindow = window;
+    }
+
+#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_7
+    if ([createdWindow respondsToSelector:@selector(setRestorable:)])
+        [createdWindow setRestorable: NO];
+#endif
+
+    NSInteger level = windowLevel(flags);
+    [createdWindow setLevel:level];
 
     if (window()->format().alphaBufferSize() > 0) {
         [createdWindow setBackgroundColor:[NSColor clearColor]];
@@ -1186,12 +1263,10 @@ QNSWindow * QCocoaWindow::createNSWindow()
     return createdWindow;
 }
 
-void QCocoaWindow::setNSWindow(QNSWindow *window)
+void QCocoaWindow::setNSWindow(NSWindow *window)
 {
-    if (!m_nsWindowDelegate) {
-        m_nsWindowDelegate = [[QNSWindowDelegate alloc] initWithQCocoaWindow:this];
-        [window setDelegate:m_nsWindowDelegate];
-    }
+    m_nsWindowDelegate = [[QNSWindowDelegate alloc] initWithQCocoaWindow:this];
+    [window setDelegate:m_nsWindowDelegate];
 
     // Prevent Cocoa from releasing the window on close. Qt
     // handles the close event asynchronously and we want to
@@ -1206,11 +1281,12 @@ void QCocoaWindow::setNSWindow(QNSWindow *window)
     }
 }
 
-void QCocoaWindow::clearNSWindow(QNSWindow *window)
+void QCocoaWindow::clearNSWindow(NSWindow *window)
 {
     [window setContentView:nil];
     [window setDelegate:nil];
     [window clearPlatformWindow];
+
     if (m_isNSWindowChild) {
         m_parentCocoaWindow->removeChildWindow(this);
     }
diff --git a/src/plugins/platforms/cocoa/qnsview.mm b/src/plugins/platforms/cocoa/qnsview.mm
index 9920d428e9..58c732de98 100644
--- a/src/plugins/platforms/cocoa/qnsview.mm
+++ b/src/plugins/platforms/cocoa/qnsview.mm
@@ -1383,12 +1383,6 @@ static QTabletEvent::TabletDevice wacomTabletDevice(NSEvent *theEvent)
     [self tryToPerform:aSelector with:self];
 }
 
-- (void)cancelOperation:(id)sender
-{
-    if (!m_platformWindow || m_platformWindow->windowShouldBehaveAsPanel())
-        [super cancelOperation:sender];
-}
-
 - (void) insertText:(id)aString replacementRange:(NSRange)replacementRange
 {
     Q_UNUSED(replacementRange)