The hellowindow OpenGL example asserts with the --multiple option

diff --git a/examples/opengl/hellowindow/hellowindow.cpp b/examples/opengl/hellowindow/hellowindow.cpp
index 1c1259de13..34eead20d3 100644
--- a/examples/opengl/hellowindow/hellowindow.cpp
+++ b/examples/opengl/hellowindow/hellowindow.cpp
@@ -95,13 +95,13 @@ void HelloWindow::exposeEvent(QExposeEvent *)
 {
     m_renderer->setAnimating(this, isExposed());
     if (isExposed())
-        m_renderer->render();
+        QMetaObject::invokeMethod(m_renderer.get(), &Renderer::render, Qt::QueuedConnection);
 }
 
 bool HelloWindow::event(QEvent *ev)
 {
     if (ev->type() == QEvent::UpdateRequest) {
-        m_renderer->render();
+        QMetaObject::invokeMethod(m_renderer.get(), &Renderer::render, Qt::QueuedConnection);
         requestUpdate();
     }
     return QWindow::event(ev);
diff --git a/examples/opengl/hellowindow/main.cpp b/examples/opengl/hellowindow/main.cpp
index 7f0be39f5d..f655f07ad6 100644
--- a/examples/opengl/hellowindow/main.cpp
+++ b/examples/opengl/hellowindow/main.cpp
@@ -50,8 +50,6 @@
 
 #include "hellowindow.h"
 
-#include <qpa/qplatformintegration.h>
-
 #include <QCommandLineParser>
 #include <QCommandLineOption>
 #include <QGuiApplication>
@@ -108,20 +106,21 @@ int main(int argc, char *argv[])
     QList<QThread *> renderThreads;
     if (multipleWindows) {
         QSharedPointer<Renderer> rendererB(new Renderer(format, rendererA.data()));
+        QSharedPointer<Renderer> rendererC(new Renderer(format, rendererA.data()));
 
         QThread *renderThread = new QThread;
         rendererB->moveToThread(renderThread);
         renderThreads << renderThread;
 
-        HelloWindow *windowB = new HelloWindow(rendererA);
+        HelloWindow *windowB = new HelloWindow(rendererB);
         windowB->setGeometry(QRect(center, windowSize).translated(delta / 2, 0));
-        windowB->setTitle(QStringLiteral("Thread A - Context A"));
+        windowB->setTitle(QStringLiteral("Thread B - Context B"));
         windowB->setVisible(true);
         windows.prepend(windowB);
 
-        HelloWindow *windowC = new HelloWindow(rendererB);
+        HelloWindow *windowC = new HelloWindow(rendererC);
         windowC->setGeometry(QRect(center, windowSize).translated(-windowSize.width() / 2, windowSize.height() + delta));
-        windowC->setTitle(QStringLiteral("Thread B - Context B"));
+        windowC->setTitle(QStringLiteral("Thread C - Context C"));
         windowC->setVisible(true);
         windows.prepend(windowC);
     }