docs: public void setPrinciple(String principle) {
  
          if (m_frame != null) {
              m_frame.removeFromParent();
              m_frame = null;
          }
          if (m_principleHandler != null) {
              m_principleHandler.selectPrincipal(principle);
          }
          if (m_onCloseCommand != null) {
              m_onCloseCommand.execute();
          }
      }