mainwindow disappearing

Quick question:

Can a main window widget be invoked from pressing a button on a dialog?

i would like to do this, but when i try, the mainwindow, appears and then disappears.

Code:

---

void to_begin::on_okButton_clicked(){
	MainWindow w;
	w.show();
}

---

to_begin is a class that inherits the dialog as well as QDialog, and the dialog form on which ok_Button is located.

Look into the FAQ.