diff --git a/5.13.2/qtbase/src/plugins/platforms/cocoa/qcocoabackingstore.mm b/5.13.2/qtbase/src/plugins/platforms/cocoa/qcocoabackingstore.mm
index 5550f05..b7a1fe9 100644
--- a/5.13.2/qtbase/src/plugins/platforms/cocoa/qcocoabackingstore.mm
+++ b/5.13.2/qtbase/src/plugins/platforms/cocoa/qcocoabackingstore.mm
@@ -165,6 +165,12 @@ void QNSWindowBackingStore::flush(QWindow *window, const QRegion &region, const
 
     const QWindow *topLevelWindow = this->window();
 
+    if (window->handle()->isForeignWindow()) {
+	NSView *view = static_cast<QCocoaWindow *>(window->handle())->view();
+	NSRect nsRect = NSRectFromCGRect(region.boundingRect().toCGRect());
+	[view displayRect:nsRect];
+	return;
+    }
     Q_ASSERT(topLevelWindow->handle() && window->handle());
     Q_ASSERT(!topLevelWindow->handle()->isForeignWindow() && !window->handle()->isForeignWindow());
 
diff --git a/5.13.2/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp b/5.13.2/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp
index c51527f..ee1107f 100644
--- a/5.13.2/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp
+++ b/5.13.2/qtbase/src/widgets/kernel/qwidgetbackingstore.cpp
@@ -107,12 +107,6 @@ void QWidgetBackingStore::qt_flush(QWidget *widget, const QRegion &region, QBack
     if (tlw->testAttribute(Qt::WA_DontShowOnScreen) || widget->testAttribute(Qt::WA_DontShowOnScreen))
         return;
 
-    // Foreign Windows do not have backing store content and must not be flushed
-    if (QWindow *widgetWindow = widget->windowHandle()) {
-        if (widgetWindow->type() == Qt::ForeignWindow)
-            return;
-    }
-
     static bool fpsDebug = qEnvironmentVariableIntValue("QT_DEBUG_FPS");
     if (fpsDebug) {
         if (!widgetBackingStore->perfFrames++)