Add notification observer on Mac

SineStriker

2023-12-27 88b5b56b6a67d93208eae3980af2f30da09dd8ae

 examples/shared/widgetframe/windowbar.h

@@ -62,7 +62,7 @@
    protected:
        WindowBar(WindowBarPrivate &d, QWidget *parent = nullptr);

        QScopedPointer<WindowBarPrivate> d_ptr;
        const std::unique_ptr<WindowBarPrivate> d_ptr;
    };

}