docs: private void initCategories() {
          Set<PortletCategory> allCategories = new HashSet<PortletCategory>();
          this.setParentCategories(this.portletCategoryRegistry.getParentCategories(this));
          for (PortletCategory childCategory : this.parentCategories) {
              allCategories.add(childCategory);
              allCategories.addAll(
                      this.portletCategoryRegistry.getAllParentCategories(childCategory));
          }
          this.setCategories(allCategories);
      }