title: Gtkmm - Proper way to close a window and then show another
body: <p>I am building a gtkmm application. The program open with a setting window asking the user to specify some information, and when sanity checks are done, this window should be closed, and the maih window of the application should open.</p>
  
  <p>Right now, opening the main window, and hiding the setting window completely close the application.
  From the setting windows, I am doing:</p>
  
  <pre><code>MainWindow* main_window = new MainWindow();
  main_window-&gt;show();                       
  this-&gt;hide();                              
  </code></pre>
  
  <p>How can I get the behavior described above ?
  Apparently, you can add and remove windows from a <code>Gtk::App</code>. Would it does what I described, and does it mean I would have to pass to my window the <code>Gtk::App</code> pointer ? Thanks.</p>