diff --git a/src/platformtheme/qdbusmenubar.cpp b/src/platformtheme/qdbusmenubar.cpp
--- a/src/platformtheme/qdbusmenubar.cpp
+++ b/src/platformtheme/qdbusmenubar.cpp
@@ -122,15 +122,20 @@
 
 void QDBusMenuBar::handleReparent(QWindow *newParentWindow)
 {
-    if (newParentWindow && newParentWindow != m_window) {
-        QWindow *oldWindow = m_window;
+    if (newParentWindow == m_window) {
+        return;
+    }
 
-        unregisterMenuBar();
-        m_window = newParentWindow;
-        registerMenuBar();
+    QWindow *oldWindow = m_window;
 
-        emit windowChanged(newParentWindow, oldWindow);
+    unregisterMenuBar();
+    m_window = newParentWindow;
+
+    if (newParentWindow) {
+        registerMenuBar();
     }
+
+    emit windowChanged(newParentWindow, oldWindow);
 }
 
 QPlatformMenu *QDBusMenuBar::menuForTag(quintptr tag) const
diff --git a/src/platformtheme/qdbusmenubar_p.h b/src/platformtheme/qdbusmenubar_p.h
--- a/src/platformtheme/qdbusmenubar_p.h
+++ b/src/platformtheme/qdbusmenubar_p.h
@@ -87,7 +87,7 @@
     QDBusPlatformMenu *m_menu;
     QDBusMenuAdaptor *m_menuAdaptor;
     QHash<quintptr, QDBusPlatformMenuItem *> m_menuItems;
-    QWindow *m_window = nullptr;
+    QPointer<QWindow> m_window;
     QString m_objectPath;
 
     QDBusPlatformMenuItem *menuItemForMenu(QPlatformMenu *menu);