OrphanQMainWindow

// OrphanQMainWindow.h

#ifndef ORPHANQMAINWINDOW_H

#define ORPHANQMAINWINDOW_H

#include <QMainWindow> 

class OrphanQMainWindow : public QMainWindow

{

    Q_OBJECT

public:

    explicit OrphanQMainWindow(QWidget *parent = 0);

protected:

    void closeEvent(QCloseEvent *event);

    void changeEvent(QEvent *event);

};

#endif // ORPHANQMAINWINDOW_H

// OrphanQMainWindow.cpp 

#include "orphanqmainwindow.h"
#include "orphanqtdialog.h"
#include <QEvent>
#include <QCloseEvent>

OrphanQMainWindow::OrphanQMainWindow(QWidget *parent) :
    QMainWindow(parent)
{
}

void OrphanQMainWindow::closeEvent(QCloseEvent *event)
{
    OrphanQDialog::CloseAll();
    event->accept();
}

void OrphanQMainWindow::changeEvent(QEvent *event)
{
    QMainWindow::changeEvent(event);

    if (event->type() != QEvent::WindowStateChange)
        return;

    Qt::WindowStates os = static_cast<QWindowStateChangeEvent*>(event)->oldState();
    Qt::WindowStates ns = windowState();

    if (ns & Qt::WindowMinimized)
    {
        OrphanQDialog::MinimizeAll();
    }

    if (os & Qt::WindowMinimized)
    {
        OrphanQDialog::RestoreAll();
    }
}