code: public boolean showPreviousPage() {
  		AbstractWizardPage previousPage;
  		try {
  			previousPage = pageHistory.pop();
  		} catch (EmptyStackException e) {
  			// Previous page is null. Updating buttons and ignoring request.
  			updateButtons();
  			return false;
  		}
  		setPage(previousPage);
  		return true;
  	}
docs: Sets the current page of this wizard to the previous page (if one exists) and removes it from the history.
  
  @return <code>true</code> if the current page was changed, otherwise <code>false</code>