@SuppressWarnings("unchecked") private void renderChildren() { elementsMap = new HashMap<>(); CategoryRenderer categoryRenderer = category.getRenderer(); for (Object o : category.getData()) { ListItem<?> element = ListItem.create(categoryRenderer, resources.defaultCategoriesListCss(), o); categoryRenderer.renderElement(element, o); elementsMap.put(o, element); if (element.getId().isEmpty()) { UIObject.ensureDebugId(element, "projectWizard-" + element.getInnerText()); } container.getElement().appendChild(element); } if (elementsMap.isEmpty()) { expandControl.getStyle().setVisibility(Style.Visibility.HIDDEN); } else { expandControl.getStyle().setVisibility(Style.Visibility.VISIBLE); } }