--- a/qtbase-everywhere-src/src/plugins/platforms/windows/qwindowswindow.cpp	2020-06-10 18:08:19.011561000 +0200
+++ b/qtbase-everywhere-src/src/plugins/platforms/windows/qwindowswindow.cpp	2020-06-10 18:06:00.357683000 +0200
@@ -684,6 +684,8 @@
             style = WS_OVERLAPPED;
         else
             style = 0;
+    } else if (embedded && (flags & Qt::FramelessWindowHint)) {
+        style = 0;                           // no border
     } else {
         style = WS_CHILD;
     }