Implement alien widgets on Mac/Cocoa.

This commit makes alien widgets opt in on a
per-widget basis on Mac, set the Qt::WA_NativeWindow
flag when creating the widget to enable. Setting
this flag on widgets that have native child or sibling
NSViews is not supported.

The main use case for alien widgets on Mac is to
improve performance for applications that have complex
user interfaces. Qt can handle thousands of widgets
per window, while Cocoa is designed to use a smaller
number of NSViews in combination with NSCells and
custom control implementations. This commit moves
us in the direction of having a few main NSViews with
"leaf" qwidgets implemented as a custom control.

8 files changed, 143 insertions, 28 deletions

diff --git a/src/gui/kernel/qapplication.cpp b/src/gui/kernel/qapplication.cpp
index 4ec2ae2..203f637 100644
--- a/src/gui/kernel/qapplication.cpp
+++ b/src/gui/kernel/qapplication.cpp
@@ -498,9 +498,7 @@ inline bool QApplicationPrivate::isAlien(QWidget *widget)
 {
     if (!widget)
         return false;
-#if defined(Q_WS_MAC) // Fake alien behavior on the Mac :)
-    return !widget->isWindow() && widget->window()->testAttribute(Qt::WA_DontShowOnScreen);
-#elif defined(Q_WS_QWS)
+#if defined(Q_WS_QWS)
     return !widget->isWindow()
 # ifdef Q_BACKINGSTORE_SUBSURFACES
         && !(widget->d_func()->maybeTopData() && widget->d_func()->maybeTopData()->windowSurface)
@@ -3013,7 +3011,7 @@ bool QApplicationPrivate::sendMouseEvent(QWidget *receiver, QMouseEvent *event,
     return result;
 }
 
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined(Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined(Q_WS_QWS) || defined(Q_WS_MAC)
 /*
     This function should only be called when the widget changes visibility, i.e.
     when the \a widget is shown, hidden or deleted. This function does nothing
@@ -3073,7 +3071,7 @@ void QApplicationPrivate::sendSyntheticEnterLeave(QWidget *widget)
     sendMouseEvent(widgetUnderCursor, &e, widgetUnderCursor, tlw, &qt_button_down, qt_last_mouse_receiver);
 #endif // QT_NO_CURSOR
 }
-#endif // Q_WS_WIN || Q_WS_X11
+#endif // Q_WS_WIN || Q_WS_X11 || Q_WS_MAC
 
 /*!
     Returns the desktop widget (also called the root window).
diff --git a/src/gui/kernel/qapplication_mac.mm b/src/gui/kernel/qapplication_mac.mm
index babfc72..c7d0e48 100644
--- a/src/gui/kernel/qapplication_mac.mm
+++ b/src/gui/kernel/qapplication_mac.mm
@@ -184,7 +184,8 @@ bool qt_mac_app_fullscreen = false;
 bool qt_scrollbar_jump_to_pos = false;
 static bool qt_mac_collapse_on_dblclick = true;
 extern int qt_antialiasing_threshold; // from qapplication.cpp
-QPointer<QWidget> qt_button_down;                // widget got last button-down
+QWidget * qt_button_down;                // widget got last button-down
+QPointer<QWidget> qt_last_mouse_receiver;
 #ifndef QT_MAC_USE_COCOA
 static bool qt_button_down_in_content; // whether the button_down was in the content area.
 static bool qt_mac_previous_press_in_popup_mode = false;
diff --git a/src/gui/kernel/qapplication_p.h b/src/gui/kernel/qapplication_p.h
index e0a6103..8653dec 100644
--- a/src/gui/kernel/qapplication_p.h
+++ b/src/gui/kernel/qapplication_p.h
@@ -514,7 +514,7 @@ public:
     int symbianResourceChange(const QSymbianEvent *symbianEvent);
 
 #endif
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
     void sendSyntheticEnterLeave(QWidget *widget);
 #endif
 
diff --git a/src/gui/kernel/qcocoaview_mac.mm b/src/gui/kernel/qcocoaview_mac.mm
index 6a16403..a1dcc2a 100644
--- a/src/gui/kernel/qcocoaview_mac.mm
+++ b/src/gui/kernel/qcocoaview_mac.mm
@@ -185,6 +185,9 @@ extern "C" {
     extern NSString *NSTextInputReplacementRangeAttributeName;
 }
 
+#ifdef ALIEN_DEBUG
+static int qCocoaViewCount = 0;
+#endif
 
 @implementation QT_MANGLE_NAMESPACE(QCocoaView)
 
@@ -195,6 +198,12 @@ extern "C" {
         [self finishInitWithQWidget:widget widgetPrivate:widgetprivate];
     }
     composingText = new QString();
+
+#ifdef ALIEN_DEBUG
+    ++qCocoaViewCount;
+    qDebug() << "init: qCocoaViewCount is" << qCocoaViewCount;
+#endif
+
     composing = false;
     sendKeyEvents = true;
     [self setHidden:YES];
@@ -414,6 +423,12 @@ extern "C" {
 {
     delete composingText;
     [[NSNotificationCenter defaultCenter] removeObserver:self];
+
+#ifdef ALIEN_DEBUG
+    --qCocoaViewCount;
+    qDebug() << "qCocoaViewCount is" << qCocoaViewCount;
+#endif
+
     [super dealloc];
 }
 
@@ -523,6 +538,10 @@ extern "C" {
             CGContextClearRect(cg, NSRectToCGRect(aRect));
         }
 
+        // Check for alien widgets, use qwidgetPrivate->drawWidget() to draw the widget if this
+        // is the case. This makes sure child widgets are drawn as well, Cocoa does not know about
+        // those and wont send them drawRect calls.
+        if (qwidget->testAttribute(Qt::WA_NativeWindow) && qt_widget_private(qwidget)->hasAlienChildren == false) {
         if (engine && !qwidget->testAttribute(Qt::WA_NoSystemBackground)
             && (qwidget->isWindow() || qwidget->autoFillBackground())
                 || qwidget->testAttribute(Qt::WA_TintedBackground)
@@ -542,6 +561,12 @@ extern "C" {
         e.setErased(true);
 #endif
         qt_sendSpontaneousEvent(qwidget, &e);
+        } else {
+           qwidget->setAttribute(Qt::WA_WState_InPaintEvent, false); // QWidgetPrivate::drawWidget sets this
+           QWidgetPrivate *qwidgetPrivate = qt_widget_private(qwidget);
+           qwidgetPrivate->drawWidget(qwidget, qrgn, QPoint(), QWidgetPrivate::DrawAsRoot | QWidgetPrivate::DrawPaintOnScreen | QWidgetPrivate::DrawRecursive, 0);
+        }
+
         if (!redirectionOffset.isNull())
             QPainter::restoreRedirected(qwidget);
         if (engine)
diff --git a/src/gui/kernel/qt_cocoa_helpers_mac.mm b/src/gui/kernel/qt_cocoa_helpers_mac.mm
index 9560952..19bae5a 100644
--- a/src/gui/kernel/qt_cocoa_helpers_mac.mm
+++ b/src/gui/kernel/qt_cocoa_helpers_mac.mm
@@ -139,7 +139,7 @@ void QMacWindowFader::performFade()
 
 extern bool qt_sendSpontaneousEvent(QObject *receiver, QEvent *event); // qapplication.cpp;
 extern QWidget * mac_mouse_grabber;
-extern QPointer<QWidget> qt_button_down; //qapplication_mac.cpp
+extern QWidget *qt_button_down; //qapplication_mac.cpp
 
 void macWindowFade(void * /*OSWindowRef*/ window, float durationSeconds)
 {
@@ -686,6 +686,12 @@ bool qt_dispatchKeyEvent(void * /*NSEvent * */ keyEvent, QWidget *widgetToGetEve
     if ([event type] == NSKeyDown) {
         qt_keymapper_private()->updateKeyMap(0, key_event, 0);
     }
+
+    // Redirect keys to alien widgets.
+    if (widgetToGetEvent->testAttribute(Qt::WA_NativeWindow) == false) {
+        widgetToGetEvent = qApp->focusWidget();
+    }
+
     if (widgetToGetEvent == 0)
         return false;
 
@@ -940,7 +946,7 @@ bool qt_mac_handleMouseEvent(void * /* NSView * */view, void * /* NSEvent * */ev
                 [static_cast<QT_MANGLE_NAMESPACE(QCocoaView) *>(tmpView) qt_qwidget];
         }
     } else {
-        extern QPointer<QWidget> qt_button_down; //qapplication_mac.cpp
+        extern QWidget * qt_button_down; //qapplication_mac.cpp
         QPoint pos;
         widgetToGetMouse = QApplicationPrivate::pickMouseReceiver(qwidget, qglobalPoint,
                                                                   pos, eventType,
@@ -952,7 +958,20 @@ bool qt_mac_handleMouseEvent(void * /* NSView * */view, void * /* NSEvent * */ev
         return false;
 
     NSPoint localPoint = [tmpView convertPoint:windowPoint fromView:nil];
-    QPoint qlocalPoint(localPoint.x, localPoint.y);
+    QPoint qlocalPoint = QPoint(localPoint.x, localPoint.y);
+
+    // Search for alien child widgets (either on this qwidget or on the popup)
+    if (widgetToGetMouse->testAttribute(Qt::WA_NativeWindow) == false || qt_widget_private(widgetToGetMouse)->hasAlienChildren) {
+        QPoint qScreenPoint = flipPoint(globalPoint).toPoint();
+#ifdef ALIEN_DEBUG
+        qDebug() << "alien mouse event" << qScreenPoint << possibleAlien;
+#endif
+        QWidget *possibleAlien =  widgetToGetMouse->childAt(qlocalPoint);
+        if (possibleAlien) {
+            qlocalPoint = possibleAlien->mapFromGlobal(widgetToGetMouse->mapToGlobal(qlocalPoint));
+            widgetToGetMouse = possibleAlien;
+        }
+    }
 
     EventRef carbonEvent = static_cast<EventRef>(const_cast<void *>([theEvent eventRef]));
     if (qt_mac_sendMacEventToWidget(widgetToGetMouse, carbonEvent))
@@ -997,7 +1016,19 @@ bool qt_mac_handleMouseEvent(void * /* NSView * */view, void * /* NSEvent * */ev
     }
     [QT_MANGLE_NAMESPACE(QCocoaView) currentMouseEvent]->localPoint = localPoint;
     QMouseEvent qme(eventType, qlocalPoint, qglobalPoint, button, buttons, keyMods);
-    qt_sendSpontaneousEvent(widgetToGetMouse, &qme);
+
+#ifdef ALIEN_DEBUG
+    qDebug() << "sending mouse event to" << widgetToGetMouse;
+#endif
+    extern QWidget *qt_button_down;
+    extern QPointer<QWidget> qt_last_mouse_receiver;
+
+    if (qwidget->testAttribute(Qt::WA_NativeWindow) && qt_widget_private(qwidget)->hasAlienChildren == false)
+        qt_sendSpontaneousEvent(widgetToGetMouse, &qme);
+    else
+        QApplicationPrivate::sendMouseEvent(widgetToGetMouse, &qme, widgetToGetMouse, qwidget, &qt_button_down,
+                                            qt_last_mouse_receiver);
+
     if (eventType == QEvent::MouseButtonPress && button == Qt::RightButton) {
         QContextMenuEvent qcme(QContextMenuEvent::Mouse, qlocalPoint, qglobalPoint, keyMods);
         qt_sendSpontaneousEvent(widgetToGetMouse, &qcme);
diff --git a/src/gui/kernel/qwidget.cpp b/src/gui/kernel/qwidget.cpp
index 2f6ec6b..b19d541 100644
--- a/src/gui/kernel/qwidget.cpp
+++ b/src/gui/kernel/qwidget.cpp
@@ -205,6 +205,7 @@ QWidgetPrivate::QWidgetPrivate(int version)
       , nativeGesturePanEnabled(0)
 #elif defined(Q_WS_MAC)
       , needWindowChange(0)
+      , hasAlienChildren(0)
       , window_event(0)
       , qd_hd(0)
 #endif
@@ -1168,6 +1169,10 @@ void QWidgetPrivate::init(QWidget *parentWidget, Qt::WindowFlags f)
     if (f & Qt::MSWindowsOwnDC)
         q->setAttribute(Qt::WA_NativeWindow);
 
+#ifdef Q_WS_MAC
+    q->setAttribute(Qt::WA_NativeWindow);
+#endif
+
     q->setAttribute(Qt::WA_QuitOnClose); // might be cleared in adjustQuitOnCloseAttribute()
     adjustQuitOnCloseAttribute();
 
@@ -1263,6 +1268,10 @@ void QWidget::create(WId window, bool initializeWindow, bool destroyOldWindow)
     }
 
     if (QWidget *parent = parentWidget()) {
+#ifdef Q_WS_MAC
+        if (testAttribute(Qt::WA_NativeWindow) == false)
+            parent->d_func()->hasAlienChildren = true;
+#endif
         if (type & Qt::Window) {
             if (!parent->testAttribute(Qt::WA_WState_Created))
                 parent->createWinId();
@@ -1433,7 +1442,7 @@ QWidget::~QWidget()
         }
     }
 
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
     else if (!internalWinId() && isVisible()) {
         qApp->d_func()->sendSyntheticEnterLeave(this);
 #ifdef Q_WS_QWS
@@ -2306,6 +2315,9 @@ QWidget *QWidget::find(WId id)
 WId QWidget::winId() const
 {
     if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) {
+#ifdef ALIEN_DEBUG
+        qDebug() << "QWidget::winId: creating native window for" << this;
+#endif
         QWidget *that = const_cast<QWidget*>(this);
         that->setAttribute(Qt::WA_NativeWindow);
         that->d_func()->createWinId();
@@ -2318,6 +2330,10 @@ WId QWidget::winId() const
 void QWidgetPrivate::createWinId(WId winid)
 {
     Q_Q(QWidget);
+
+#ifdef ALIEN_DEBUG
+    qDebug() << "QWidgetPrivate::createWinId for" << q << winid;
+#endif
     const bool forceNativeWindow = q->testAttribute(Qt::WA_NativeWindow);
     if (!q->testAttribute(Qt::WA_WState_Created) || (forceNativeWindow && !q->internalWinId())) {
         if (!q->isWindow()) {
@@ -2360,6 +2376,9 @@ Ensures that the widget has a window system identifier, i.e. that it is known to
 void QWidget::createWinId()
 {
     Q_D(QWidget);
+#ifdef ALIEN_DEBUG
+    qDebug()  << "QWidget::createWinId" << this;
+#endif
 //    qWarning("QWidget::createWinId is obsolete, please fix your code.");
     d->createWinId();
 }
@@ -5249,7 +5268,15 @@ void QWidgetPrivate::drawWidget(QPaintDevice *pdev, const QRegion &rgn, const QP
             QPaintEngine *paintEngine = pdev->paintEngine();
             if (paintEngine) {
                 setRedirected(pdev, -offset);
+#ifdef Q_WS_MAC
+                // (Alien support) Special case for Mac when redirecting: If the paint device
+                // is of the Widget type we need to set WA_WState_InPaintEvent since painting
+                // outside the paint event is not supported on QWidgets. The attributeis
+                // restored further down.
+                if (pdev->devType() == QInternal::Widget)
+                    static_cast<QWidget *>(pdev)->setAttribute(Qt::WA_WState_InPaintEvent);
 
+#endif
                 if (sharedPainter)
                     paintEngine->d_func()->systemClip = toBePainted;
                 else
@@ -5290,6 +5317,10 @@ void QWidgetPrivate::drawWidget(QPaintDevice *pdev, const QRegion &rgn, const QP
 
             //restore
             if (paintEngine) {
+#ifdef Q_WS_MAC
+                if (pdev->devType() == QInternal::Widget)
+                    static_cast<QWidget *>(pdev)->setAttribute(Qt::WA_WState_InPaintEvent, false);
+#endif
                 restoreRedirected();
                 if (!sharedPainter)
                     paintEngine->d_func()->systemRect = QRect();
@@ -7322,7 +7353,7 @@ void QWidgetPrivate::hide_helper()
     // next bit tries to move the focus if the focus widget is now
     // hidden.
     if (wasVisible) {
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
         qApp->d_func()->sendSyntheticEnterLeave(q);
 #endif
 
@@ -7454,7 +7485,7 @@ void QWidget::setVisible(bool visible)
 
             d->show_helper();
 
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
             qApp->d_func()->sendSyntheticEnterLeave(this);
 #endif
         }
@@ -7569,7 +7600,7 @@ void QWidgetPrivate::hideChildren(bool spontaneous)
                 widget->d_func()->hide_sys();
             }
         }
-#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined (Q_WS_QWS) || defined(Q_WS_MAC)
         qApp->d_func()->sendSyntheticEnterLeave(widget);
 #endif
 #ifndef QT_NO_ACCESSIBILITY
@@ -9787,7 +9818,7 @@ void QWidget::setParent(QWidget *parent, Qt::WindowFlags f)
         desktopWidget = parent;
     bool newParent = (parent != parentWidget()) || !wasCreated || desktopWidget;
 
-#if defined(Q_WS_X11) || defined(Q_WS_WIN)
+#if defined(Q_WS_X11) || defined(Q_WS_WIN) || defined(Q_WS_MAC)
     if (newParent && parent && !desktopWidget) {
         if (testAttribute(Qt::WA_NativeWindow) && !qApp->testAttribute(Qt::AA_DontCreateNativeWidgetSiblings))
             parent->d_func()->enforceNativeChildren();
@@ -10433,7 +10464,7 @@ void QWidget::setAttribute(Qt::WidgetAttribute attribute, bool on)
     }
     case Qt::WA_PaintOnScreen:
         d->updateIsOpaque();
-#if defined(Q_WS_WIN) || defined(Q_WS_X11)
+#if defined(Q_WS_WIN) || defined(Q_WS_X11) || defined(Q_WS_MAC)
         // Recreate the widget if it's already created as an alien widget and
         // WA_PaintOnScreen is enabled. Paint on screen widgets must have win id.
         // So must their children.
diff --git a/src/gui/kernel/qwidget_mac.mm b/src/gui/kernel/qwidget_mac.mm
index dcb87fc..6d8c97b 100644
--- a/src/gui/kernel/qwidget_mac.mm
+++ b/src/gui/kernel/qwidget_mac.mm
@@ -459,7 +459,13 @@ static bool qt_isGenuineQWidget(OSViewRef ref)
 
 bool qt_isGenuineQWidget(const QWidget *window)
 {
-    return window && qt_isGenuineQWidget(OSViewRef(window->winId()));
+    if (!window)
+        return false;
+
+    if (!window->internalWinId())
+        return true;  //alien
+
+    return qt_isGenuineQWidget(OSViewRef(window->internalWinId()));
 }
 
 Q_GUI_EXPORT OSWindowRef qt_mac_window_for(const QWidget *w)
@@ -2608,7 +2614,16 @@ void QWidgetPrivate::create_sys(WId window, bool initializeWindow, bool destroyO
         }
     } else {
         data.fstrut_dirty = false; // non-toplevel widgets don't have a frame, so no need to update the strut
-        if(OSViewRef osview = qt_mac_create_widget(q, this, qt_mac_nativeview_for(parentWidget))) {
+
+#ifdef QT_MAC_USE_COCOA
+        if (q->testAttribute(Qt::WA_NativeWindow) == false ||
+            q->internalWinId() != 0) {
+#ifdef ALIEN_DEBUG
+            qDebug() << "Skipping native widget creation for" << this;
+#endif
+        } else
+#endif
+        if (OSViewRef osview = qt_mac_create_widget(q, this, qt_mac_nativeview_for(parentWidget))) {
 #ifndef QT_MAC_USE_COCOA
             HIRect bounds = CGRectMake(data.crect.x(), data.crect.y(), data.crect.width(), data.crect.height());
             HIViewSetFrame(osview, &bounds);
@@ -2869,9 +2884,12 @@ void QWidgetPrivate::setParent_sys(QWidget *parent, Qt::WindowFlags f)
     q->setAttribute(Qt::WA_WState_Visible, false);
     q->setAttribute(Qt::WA_WState_Hidden, false);
     adjustFlags(data.window_flags, q);
-    // keep compatibility with previous versions, we need to preserve the created state
-    // (but we recreate the winId for the widget being reparented, again for compatibility)
-    if (wasCreated || (!q->isWindow() && parent->testAttribute(Qt::WA_WState_Created))) {
+    // keep compatibility with previous versions, we need to preserve the created state.
+    // (but we recreate the winId for the widget being reparented, again for compatibility,
+    // unless this is an alien widget. )
+    const bool nonWindowWithCreatedParent = !q->isWindow() && parent->testAttribute(Qt::WA_WState_Created);
+    const bool nativeWidget = q->internalWinId() != 0;
+    if (wasCreated || nativeWidget && nonWindowWithCreatedParent) {
         createWinId();
         if (q->isWindow()) {
 #ifndef QT_MAC_USE_COCOA
@@ -2955,7 +2973,7 @@ void QWidgetPrivate::setParent_sys(QWidget *parent, Qt::WindowFlags f)
 QPoint QWidget::mapToGlobal(const QPoint &pos) const
 {
     Q_D(const QWidget);
-    if (!testAttribute(Qt::WA_WState_Created)) {
+    if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) {
         QPoint p = pos + data->crect.topLeft();
         return isWindow() ?  p : parentWidget()->mapToGlobal(p);
     }
@@ -2982,7 +3000,7 @@ QPoint QWidget::mapToGlobal(const QPoint &pos) const
 QPoint QWidget::mapFromGlobal(const QPoint &pos) const
 {
     Q_D(const QWidget);
-    if (!testAttribute(Qt::WA_WState_Created)) {
+    if (!testAttribute(Qt::WA_WState_Created) || !internalWinId()) {
         QPoint p = isWindow() ?  pos : parentWidget()->mapFromGlobal(pos);
         return p - data->crect.topLeft();
     }
@@ -3320,10 +3338,20 @@ void QWidgetPrivate::update_sys(const QRegion &rgn)
     }
 #else
     // Cocoa doesn't do regions, it seems more efficient to just update the bounding rect instead of a potential number of message passes for each rect.
-    const QRect &boundingRect = rgn.boundingRect();
-    [qt_mac_nativeview_for(q) setNeedsDisplayInRect:NSMakeRect(boundingRect.x(),
-                                                            boundingRect.y(), boundingRect.width(),
-                                                            boundingRect.height())];
+    const QRect & boundingRect = rgn.boundingRect();
+
+    // Alien support: get the first native ancestor widget (will be q itself in the non-alien case),
+    // map the coordinates from q space to NSView space and invalidate the rect.
+    QWidget *nativeParent = q->internalWinId() ? q : q->nativeParentWidget();
+    if (nativeParent == 0)
+            return;
+    const QRect nativeBoundingRect = QRect(
+            QPoint(q->mapTo(nativeParent, boundingRect.topLeft())),
+            QSize(boundingRect.size()));
+
+    [qt_mac_nativeview_for(nativeParent) setNeedsDisplayInRect:NSMakeRect(nativeBoundingRect.x(),
+                                                            nativeBoundingRect.y(), nativeBoundingRect.width(),
+                                                            nativeBoundingRect.height())];
 #endif
 }
 
diff --git a/src/gui/kernel/qwidget_p.h b/src/gui/kernel/qwidget_p.h
index efd9a0a..2cb8586 100644
--- a/src/gui/kernel/qwidget_p.h
+++ b/src/gui/kernel/qwidget_p.h
@@ -720,6 +720,7 @@ public:
 #elif defined(Q_WS_MAC) // <--------------------------------------------------------- MAC
     // This is new stuff
     uint needWindowChange : 1;
+    uint hasAlienChildren : 1;
 
     // Each wiget keeps a list of all its child and grandchild OpenGL widgets.
     // This list is used to update the gl context whenever a parent and a granparent