code: protected void enableComboMode() {
  
          String value = m_selectBox.getFormValueAsString();
          m_selectBox.removeFromParent();
          m_comboMode = true;
          m_panel.add(m_comboBox);
          m_comboBox.setFormValueAsString(value);
          m_comboBox.setErrorMessage(m_error);
          m_comboBox.setEnabled(m_selectBox.isEnabled());
      }
docs: Switches to combo box mode.<p>