public List<String> getHiddenWidgetIds() {
   DashboardPanel<T> dashboard = getDashboardPanel();
   List<String> ids = new ArrayList<String>();
   for (AbstractWidget<T> widget : dashboard.getWidgets()) {
     if (widget.isHidden()) ids.add(widget.getId());
   }
   return ids;
 }
 public List<IWidgetType<T>> getAvailableWidgetTypes() {
   DashboardPanel<T> dashboard = getDashboardPanel();
   return registry.lookupByDomainAndTab(
       dashboard.getDomain(), dashboard.getTab(), dashboard.getWidgetsFilter());
 }