code: public DialogPage addForm(Form form) {
  		DialogPage page = createDialogPage(form);
  		addPage(page);
  		return page;
  	}
docs: Adds a new page to the list of pages managed by this CompositeDialogPage.
  The page is created by wrapping the form page in a FormBackedDialogPage.
  
  @param form the form page to be insterted
  @return the DialogPage that wraps formPage