From c561b7197bff1333dcc340b3a53cace8887ef243 Mon Sep 17 00:00:00 2001
From: Wladimir Leuschner <wladimir.leuschner@qt.io>
Date: Wed, 31 Jul 2024 13:54:32 +0200
Subject: [PATCH] Update QMdiSubWindow after windowFlags were changed

Adding or removing close/maximize/minimize buttons to an already
existing QMdiSubWindow is only visible after the window is repainted.
This patch repaints the QMdiSubWindow at the end of setWindowFlags.

Fixes: QTBUG-125778
Pick-to: 6.7
Change-Id: Ibdf136621bf70337a2af29dfcfd10b60dde11e15
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 6520ed0f2567c5a8fd680dccbff59c5ef8fc89c2)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/widgets/widgets/qmdisubwindow.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/widgets/widgets/qmdisubwindow.cpp b/src/widgets/widgets/qmdisubwindow.cpp
index d8700e3df2d..58762a3a1ab 100644
--- a/src/widgets/widgets/qmdisubwindow.cpp
+++ b/src/widgets/widgets/qmdisubwindow.cpp
@@ -2095,6 +2095,7 @@ void QMdiSubWindowPrivate::setVisible(WindowStateAction action, bool visible)
                                        (controlContainer->controllerWidget())) {
         ctrlWidget->setControlVisible(action, visible);
     }
+    q->update();
 }
 
 #ifndef QT_NO_ACTION
@@ -2867,6 +2868,13 @@ bool QMdiSubWindow::event(QEvent *event)
         showToolTip(static_cast<QHelpEvent *>(event), this, d->titleBarOptions(),
                     QStyle::CC_TitleBar, d->hoveredSubControl);
         break;
+#endif
+#ifndef QT_NO_ACTION
+    case QEvent::ActionAdded:
+    case QEvent::ActionChanged:
+    case QEvent::ActionRemoved:
+        update();
+        break;
 #endif
     default:
         break;