code: public void startWizard(AbstractWizardPage startPage) {
  		if (startPage == null) {
  			throw new IllegalArgumentException("startPage can't be null");
  		}
  		if (currentPage != null) {
  			wizard.getWizardPageContainer().remove(currentPage);
  			pageHistory.clear();
  			currentPage = null;
  		}
  		showNextPage(startPage);
  	}
docs: Starts (or restarts) the wizard with the given start page.
  
  @param startPage
  the page to start (or restart) the wizard with