How to get focus back to main window if non-modal dialog is closed?

[falconium]

DIALOG:

Extract from the constructor of dialog:

setWindowFlags(Qt::WindowTitleHint | Qt::Dialog | Qt::WindowMaximizeButtonHint | Qt::WindowCloseButtonHint | Qt::CustomizeWindowHint);
setModal(false);

setWindowFlags(Qt::WindowTitleHint | Qt::Dialog | Qt::WindowMaximizeButtonHint | Qt::WindowCloseButtonHint | Qt::CustomizeWindowHint);
setModal(false);

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cpp:

void FindDialog::closeEvent(QCloseEvent *e)
{
    emit closing(true);
    QDialog::closeEvent(e);
}

void FindDialog::closeEvent(QCloseEvent *e)
{
    emit closing(true);
    QDialog::closeEvent(e);
}

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h:

protected:
    void closeEvent(QCloseEvent *e);
 
signals:
    void closing(bool visible);

protected:
    void closeEvent(QCloseEvent *e);

signals:
    void closing(bool visible);

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MAIN WINDOW:

cpp:

findDialog = new FindDialog;
findDialog->setVisible(false);
findDialog->setMeasurements(&measurements);
connect(findDialog, SIGNAL(closing(bool)), this, SLOT(setShown(bool)));

findDialog = new FindDialog;
findDialog->setVisible(false);
findDialog->setMeasurements(&measurements);
connect(findDialog, SIGNAL(closing(bool)), this, SLOT(setShown(bool)));

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h:

FindDialog *findDialog;

FindDialog *findDialog;

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Even if I change setShown to setFocus it doesn't make any difference.
How could I get back the focus to main window? It is crucial if user meanwhile activated a different application and then clicked back on dialog and closes it...

findDialog->setVisible(true); is called when a menu item is triggered.