QWidget is not updating when using show instead of exec

Question

In my project, I need to create a non-blocking QWizard on the top of my Mfc application. To do this, I followed the instruction here (link)

Doing this have a strange side-effect, it looks like that my UI is not updating properly when I am clicking my QRadioButton inside my QWizardPage. See following screenshots :

1-First step in my QWizard. Everything looks good

2-I clicked on a QRadioButton. See, the "Next" button is in a weird state.

3-I clicked on the second QRadioButton. See, both QRadioButton look selected. (Yes, they are mutually exclusive!

4-Now, if I am doing a "mouse over", over the "Next" button and over QRadioButton, this forces an update and my UI is fine

My question is : How to update properly my UI when using show instead of exec? (I did try with exec and my UI is updating properly)

I guess that main thread is not updating my UI if I use show?

Thank you.

EDIT

Here is the code of the function that instantiate the wizard :

void QtMfcFacade::startDevicesConfigurationWizard(HWND hWnd)
{
    QWinWidget* win = new QWinWidget( hWnd );
    win->showCentered();
    DevicesConfigurationWizard *devicesConfigurationWizardUI = new DevicesConfigurationWizard(win);
    devicesConfigurationWizardUI->setModal(true);
    devicesConfigurationWizardUI->show();
}

THe following is my QWizard class :

DevicesConfigurationWizard::DevicesConfigurationWizard(QWidget *parent, Qt::WFlags flags)
    : QWizard(parent, flags),
{
    ui.setupUi(this);
    this->setWindowFlags( ( (this->windowFlags() | Qt::CustomizeWindowHint)
                       & ~Qt::WindowCloseButtonHint & ~Qt::WindowContextHelpButtonHint) );
    this->setAttribute( Qt::WA_DeleteOnClose, true );
    connect(this, SIGNAL(currentIdChanged(int)), this, SLOT(onClick(int)));
}

void DevicesConfigurationWizard::onClick(int pageId)
{
    if (m_currentPageId < pageId)
    {        
        //user clicked next button.
        switch (pageId)
        {
            case PAGE_NUMBER_SINGLE_USER:
            {
                setupSingleUserPage();
                break;
            }
            default :
            {
                //problem!!!
            }
        }
        m_currentPageId = pageId;
    }
}

void DevicesConfigurationWizard::onRadioButtonClick()
{
    this->button(this->NextButton)->setEnabled(true);
    this->button(this->FinishButton)->setEnabled(true);
}

void DevicesConfigurationWizard::setupSingleUserPage()
{
    this->button(this->NextButton)->setEnabled(false);
    int newPositionY = 0;
        QVBoxLayout* layout = ui.wpSINGLE_USER->findChild<QVBoxLayout*>("verticalLayout");
        for (vector<Events::VCS::PnPDevice>::const_iterator it=m_devices.begin(); it!=m_devices.end(); it++)
        {
            if (it->type == Events::VCS::HEADSET)
            {
                //add a radio button
                stringstream text;
                text <<  (it->name) << " " << (it->serialNumber) ;
                QRadioButton* radioButton = new QRadioButton(this->ui.wpSINGLE_USER);
                radioButton->setGeometry(X, Y + newPositionY, WIDHT, HEIGHT);
                radioButton->setText(text.str().c_str());
                radioButton->setIconSize(QSize(HEIGHT,HEIGHT));
                newPositionY = newPositionY + HEIGHT;
                layout->insertWidget(0, radioButton);
                connect(radioButton, SIGNAL(clicked()), this, SLOT(onRadioButtonClick()));
            }
    }
}

EDIT trying to force update does not resolved problem so far

void DevicesConfigurationWizard::onRadioButtonClick()
{
    this->button(this->NextButton)->setEnabled(true);
    this->button(this->FinishButton)->setEnabled(true);
    QWidget::update();
    this->update();
    this->button(this->NextButton)->update();
    QList<QRadioButton*> listButton = ui.wpSINGLE_USER->findChildren<QRadioButton*>();
    listButton[0]->update();
    listButton[1]->update();
    QApplication::processEvents();
}

Answer 1

The problem is comming from my Mfc application. A timer was sending a timer event to the event loop every 100 miliseconds, so, my Qt application was not able to update properly. So, what I did, I added QCoreApplication::processEvents() into OnTimer, on Mfc application.

This way, QCoreApplication::processEvents is being call every 100 milisedonds and my Qt UI is now correctly updated.