code: protected void addClassEditors (BuilderModel model, String cprefix)
      {
          List<ComponentClass> classes = model.getComponentClasses();
          int size = classes.size();
          for (int ii = 0; ii < size; ii++) {
              ComponentClass cclass = classes.get(ii);
              if (!cclass.name.startsWith(cprefix)) {
                  continue;
              }
              List<Integer> ccomps = model.getComponents(cclass);
              if (ccomps.size() > 0) {
                  add(new ClassEditor(model, cclass, ccomps));
              } else {
                  log.info("Not creating editor for empty class " +
                           "[class=" + cclass + "].");
              }
          }
      }
docs: Adds editor user interface elements for each component class to
  allow the user to select the desired component.