1 files changed, 32 insertions, 7 deletions

diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index b3b07cc8dd..f3faccbc14 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -549,6 +549,18 @@ QWindowsWindow::WindowData
             qDebug().nospace() << "Created desktop window " << w << result.hwnd;
         return result;
     }
+    if ((flags & Qt::WindowType_Mask) == Qt::ForeignWindow) {
+        result.hwnd = reinterpret_cast<HWND>(w->winId());
+        Q_ASSERT(result.hwnd);
+        const LONG_PTR style = GetWindowLongPtr(result.hwnd, GWL_STYLE);
+        const LONG_PTR exStyle = GetWindowLongPtr(result.hwnd, GWL_EXSTYLE);
+        result.geometry = frameGeometry(result.hwnd, !GetParent(result.hwnd));
+        result.frame = QWindowsGeometryHint::frame(style, exStyle);
+        result.embedded = false;
+        if (QWindowsContext::verboseWindows)
+            qDebug() << "Foreign window: " << w << result.hwnd << result.geometry << result.frame;
+        return result;
+    }
 
     const HINSTANCE appinst = (HINSTANCE)GetModuleHandle(0);
 
@@ -962,7 +974,7 @@ void QWindowsWindow::destroyWindow()
             }
         }
 #endif // !Q_OS_WINCE
-        if (m_data.hwnd != GetDesktopWindow())
+        if (m_data.hwnd != GetDesktopWindow() && window()->type() != Qt::ForeignWindow)
             DestroyWindow(m_data.hwnd);
         context->removeWindow(m_data.hwnd);
         m_data.hwnd = 0;
@@ -1483,14 +1495,27 @@ void QWindowsWindow::handleWindowStateChange(Qt::WindowState state)
         handleHidden();
         QWindowSystemInterface::flushWindowSystemEvents(); // Tell QQuickWindow to stop rendering now.
         break;
-    case Qt::WindowNoState:
+    case Qt::WindowNoState: {
         // QTBUG-17548: We send expose events when receiving WM_Paint, but for
-        // layered windows, we won't receive any WM_Paint.
-        if (GetWindowLongPtr(m_data.hwnd, GWL_EXSTYLE) & WS_EX_LAYERED) {
-            fireExpose(QRegion(0, 0, window()->width(), window()->height()));
-            if (!QWindowsContext::instance()->asyncExpose())
-                QWindowSystemInterface::flushWindowSystemEvents();
+        // layered windows and transient children, we won't receive any WM_Paint.
+        QWindow *w = window();
+        bool exposeEventsSent = false;
+        if (isLayered()) {
+            fireExpose(QRegion(0, 0, w->width(), w->height()));
+            exposeEventsSent = true;
         }
+        foreach (QWindow *child, QGuiApplication::allWindows()) {
+            if (child != w && child->isVisible() && child->transientParent() == w) {
+                QWindowsWindow *platformWindow = QWindowsWindow::baseWindowOf(child);
+                if (platformWindow->isLayered()) {
+                    platformWindow->fireExpose(QRegion(0, 0, child->width(), child->height()));
+                    exposeEventsSent = true;
+                }
+            }
+        }
+        if (exposeEventsSent && !QWindowsContext::instance()->asyncExpose())
+            QWindowSystemInterface::flushWindowSystemEvents();
+    }
         break;
     default:
         break;