firePropertyChange(MODEL_CHANGED_PROPERTY, oldDataModel, dataModel);
firePropertyChange("model", oldDataModel, dataModel);
  public void setModel(ComboBoxModel newDataModel)  {    // dataModel is null if it this method is called from inside the constructors.    if(dataModel != null) {	// Prevents unneccessary updates.	if (dataModel == newDataModel)      return;    	// Removes itself (as DataListener) from the to-be-replaced model.      dataModel.removeListDataListener(this);    }    /* Adds itself as a DataListener to the new model.     * It is intentioned that this operation will fail with a NullPointerException if the     * caller delivered a null argument.     */    newDataModel.addListDataListener(this);    // Stores old data model for event notification.    ComboBoxModel oldDataModel = dataModel;    dataModel = newDataModel;    // Notifies the listeners of the model change.    firePropertyChange(MODEL_CHANGED_PROPERTY, oldDataModel, dataModel);  }