Make better code structure for border handlers

Sine Striker

2023-12-13 a51b5688e1c33d3ce96b48c869603b00f908f513

 examples/mainwindow/mainwindow.h

@@ -7,6 +7,9 @@
public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

protected:
    void installWindowAgent();
};

#endif // MAINWINDOW_H