stdin.patch

diff --git c/src/gui/kernel/qplatformintegration.cpp i/src/gui/kernel/qplatformintegration.cpp
index a53f0d09d71..1427db5c614 100644
--- c/src/gui/kernel/qplatformintegration.cpp
+++ i/src/gui/kernel/qplatformintegration.cpp
@@ -450,6 +450,9 @@ Qt::WindowState QPlatformIntegration::defaultWindowState(Qt::WindowFlags flags)
     if (flags & Qt::Popup & ~Qt::Window)
         return Qt::WindowNoState;
 
+     if (flags & Qt::SubWindow)
+        return Qt::WindowNoState;
+
     if (styleHint(QPlatformIntegration::ShowIsFullScreen).toBool())
         return Qt::WindowFullScreen;
     else if (styleHint(QPlatformIntegration::ShowIsMaximized).toBool())
diff --git c/src/widgets/kernel/qwindowcontainer.cpp i/src/widgets/kernel/qwindowcontainer.cpp
index b4d889fdfa0..54845444446 100644
--- c/src/widgets/kernel/qwindowcontainer.cpp
+++ i/src/widgets/kernel/qwindowcontainer.cpp
@@ -234,6 +234,8 @@ QWindowContainer::QWindowContainer(QWindow *embeddedWindow, QWidget *parent, Qt:
     d->fakeParent.setObjectName(windowName + QLatin1String("ContainerFakeParent"));
 
     d->window->setParent(&d->fakeParent);
+    d->window->setFlag(Qt::SubWindow);
+
     setAcceptDrops(true);
 
     connect(QGuiApplication::instance(), SIGNAL(focusWindowChanged(QWindow*)), this, SLOT(focusWindowChanged(QWindow*)));