title: Google Apps Script Popup to maintain widgets when re-opened
body: <p>I'm working on a script using Google Apps Script with UiApp and I need to maintain the widgets in a popup after reopen it.</p>
  
  <p>e.g. Open a popup, create some listboxes, close the popup and on reopen the same listboxes should be there.</p>
  
  <p>Any sugestion?</p>