minor improve quick demo

Zhao Yuhang

2023-12-18 44fee9aa1e3087635d1394612c6f6ceab44ba7b0

 src/widgets/widgetwindowagent_p.h

@@ -16,6 +16,10 @@

        // Host
        QWidget *hostWidget{};
#ifdef Q_OS_MAC
        QWidget *systemButtonAreaWidget{};
        std::unique_ptr<QObject> systemButtonAreaWidgetEventFilter;
#endif

#ifdef Q_OS_WINDOWS
        void setupWindows10BorderWorkaround();