java.lang.IllegalArgumentException: adding a window to a container

I'm trying to insert a design of a frame to put it inside a Jlist, but it throws me this error java.lang.IllegalArgumentException: adding a window to a container

public class clsRender implements ListCellRenderer, Renderer{

private final JTextField observacion;
private final JLabel fecha;
private final jfrmGestion gestion;

public clsRender() {
    this.gestion = new jfrmGestion();
    this.observacion = gestion.getjTextField1();
    this.fecha = gestion.getjLabel1();
}

@Override
public Component getListCellRendererComponent(JList list, Object value, int index, boolean isSelected, boolean cellHasFocus) {
   String [] valor = value.toString().split("/");
   observacion.setText(valor[0]);
   fecha.setText(valor[1]);
   if(!isSelected){
       gestion.setBackground(list.getBackground());
   }
   else{
       gestion.setBackground(list.getSelectionBackground());
   }
   return gestion;
}

@Override
public void setValue(Object aValue, boolean isSelected) {
    throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

@Override
public Component getComponent() {
    throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}

That's the class I was designing with, but I do not know why this error occurs

private void CargarDatos(){
    ListHistorial.setCellRenderer(new clsRender());
    model = new DefaultListModel();
    ListHistorial.setModel(model);
}

private void LlenarHistorial(){
    try {
        cn = conecta.Conectar();
        stmt = cn.createStatement();
        rs = stmt.executeQuery("SELECT * FROM tb_observaciones WHERE id_alquiler = "+id_alquiler);
        while(rs.next()){
            String observacion = rs.getString(2);
            Date fecha = rs.getDate(4);
            model.addElement(observacion+"/"+fecha);
        }
        cn.close();
    } catch (SQLException e) {
        JOptionPane.showMessageDialog(null, "Error al cargar los datos del sistema");
    }
}