5 files changed, 32 insertions, 23 deletions
diff --git a/src/corelib/kernel/qcoreevent.h b/src/corelib/kernel/qcoreevent.h
index 5487703..fa472e6 100644
--- a/src/corelib/kernel/qcoreevent.h
+++ b/src/corelib/kernel/qcoreevent.h
@@ -264,6 +264,7 @@ public:
         GrabKeyboard = 188,
         UngrabKeyboard = 189,
         CocoaRequestModal = 190,                // Internal for requesting an application modal Cocoa Window
+        MacGLClearDrawable = 191,               // Internal Cocoa, the window has changed, so we must clear
 
         // 512 reserved for Qt Jambi's MetaCall event
         // 513 reserved for Qt Jambi's DeleteOnMainThread event
diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index 118d54c..670226b 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -946,6 +946,27 @@ extern "C" {
     }
 }
 
+- (void)viewWillMoveToWindow:(NSWindow *)window
+{
+    if (qwidget->windowFlags() & Qt::MSWindowsOwnDC
+          && (window != [self window])) { // OpenGL Widget
+        // Create a stupid ClearDrawable Event
+        QEvent event(QEvent::MacGLClearDrawable);
+        qApp->sendEvent(qwidget, &event);
+    }
+}
+
+- (void)viewDidMoveToWindow
+{
+    if (qwidget->windowFlags() & Qt::MSWindowsOwnDC && [self window]) {
+        // call update paint event
+        qwidgetprivate->needWindowChange = true;
+        QEvent event(QEvent::MacGLWindowChange);
+        qApp->sendEvent(qwidget, &event);
+    }
+}
+
+
 // NSTextInput Protocol implementation
 
 - (void) insertText:(id)aString
diff --git a/src/opengl/qgl.cpp b/src/opengl/qgl.cpp
index 303b5e2..99df658 100644
--- a/src/opengl/qgl.cpp
+++ b/src/opengl/qgl.cpp
@@ -3235,6 +3235,10 @@ bool QGLWidget::event(QEvent *e)
             update();
         }
         return true;
+#  if defined(QT_MAC_USE_COCOA)
+    } else if (e->type() == QEvent::MacGLClearDrawable) {
+        d->glcx->d_ptr->clearDrawable();
+#  endif
     }
 #endif
 
diff --git a/src/opengl/qgl_mac.mm b/src/opengl/qgl_mac.mm
index 314c659..3dbdaec 100644
--- a/src/opengl/qgl_mac.mm
+++ b/src/opengl/qgl_mac.mm
@@ -87,29 +87,6 @@ QT_FORWARD_DECLARE_CLASS(QWidget)
 QT_FORWARD_DECLARE_CLASS(QWidgetPrivate)
 QT_FORWARD_DECLARE_CLASS(QGLWidgetPrivate)
 
-@interface QT_MANGLE_NAMESPACE(QCocoaOpenGLView) : QT_MANGLE_NAMESPACE(QCocoaView)
-{
-}
-- (id)initWithQWidget:(QWidget *)widget widgetPrivate:(QWidgetPrivate *)widgetprivate;
-@end
-
-@implementation QT_MANGLE_NAMESPACE(QCocoaOpenGLView)
-- (id)initWithQWidget:(QWidget *)widget widgetPrivate:(QWidgetPrivate *)widgetprivate
-{
-    self = [super initWithQWidget:widget widgetPrivate:widgetprivate];
-    [[NSNotificationCenter defaultCenter] addObserver:self
-                                   selector:@selector(_surfaceNeedsUpdate:)
-                                   name:NSViewGlobalFrameDidChangeNotification
-                                   object:self];
-    return self;
-}
-
-- (void) _surfaceNeedsUpdate:(NSNotification*)notification
-{
-    Q_UNUSED(notification);
-    static_cast<QGLWidgetPrivate *>(qwidgetprivate)->glcx->updatePaintDevice();
-}
-@end
 QT_BEGIN_NAMESPACE
 
 void *qt_current_nsopengl_context()
@@ -435,6 +412,11 @@ void *QGLContextPrivate::tryFormat(const QGLFormat &format)
 #endif
 }
 
+void QGLContextPrivate::clearDrawable()
+{
+    [static_cast<NSOpenGLContext *>(cx) clearDrawable];
+}
+
 /*!
     \bold{Mac OS X only:} This virtual function tries to find a visual that
     matches the format, reducing the demands if the original request
diff --git a/src/opengl/qgl_p.h b/src/opengl/qgl_p.h
index b15eebc..1214f20 100644
--- a/src/opengl/qgl_p.h
+++ b/src/opengl/qgl_p.h
@@ -234,6 +234,7 @@ public:
 #if defined(Q_WS_MAC)
     bool update;
     void *tryFormat(const QGLFormat &format);
+    void clearDrawable();
 #endif
     QGLFormat glFormat;
     QGLFormat reqFormat;