@Override
  public boolean isAlwaysShowsPlus(StructureViewTreeElement element) {
    for (ElementInfoProvider p : getModels().filter(ElementInfoProvider.class)) {
      if (p.isAlwaysShowsPlus(element)) return true;
    }
    return false;
  }
@Override
  public boolean isAlwaysShowsPlus(StructureViewTreeElement element)