Hidden is just a text box you can’t see and does not take up space on the page. See Figure A-13.

function Hidden() {
  var mydoc = SpreadsheetApp.getActiveSpreadsheet();
  var app = UiApp.createApplication().setTitle('Hidden'); 
  var mainPanel = app.createVerticalPanel().setId('mainPanel');
  app.add(mainPanel);

  //one label above and one below for reference.  
  var label1 = app.createLabel('Hidden Box Below');
  mainPanel.add(label1);
  
  //This is the hidden box with a value ready to go
  var hiddenBox = app.createHidden().setName('hiddenBox').setValue("Found Me");
  mainPanel.add(hiddenBox);
  
  //after button press we show a lable to indicate where the box "is"
  var hiddenLabel = app.createLabel().setId('hiddenLabel').setVisible(false);
  mainPanel.add(hiddenLabel);
  
  var label2 = app.createLabel('Hidden Box Above');
  m....