docs: @Nonnull
    public final EChange setType (@Nonnull final EBootstrapPanelType eType)
    {
      ValueEnforcer.notNull (eType, "Type");
      if (eType.equals (m_eType))
        return EChange.UNCHANGED;
  
      removeClass (m_eType);
      addClass (eType);
      m_eType = eType;
      return EChange.CHANGED;
    }