title: How to remove selected value in ComboBox
body: <p>I want to remove all the items in ComboBox and refill it with some other items when another button clicks .I do it using removeAll() but the previously selected value is still there in the combo.This is what i did.</p>
  
  <pre><code>@AutoGenerated
  private AbsoluteLayout mainLayout;
  @AutoGenerated
  private GridLayout gridLayout_1;
  @AutoGenerated
  private HorizontalLayout horizontalLayout_1;
  @AutoGenerated
  private Button cancelBtn;
  @AutoGenerated
  private Button saveBtn;
  @AutoGenerated
  private TextField openingHoursTf;
  @AutoGenerated
  private Label label_10;
  @AutoGenerated
  private TextField emailTf;
  @AutoGenerated
  private Label label_9;
  @AutoGenerated
  private TextField phoneTf;
  @AutoGenerated
  private Label label_3;
  @AutoGenerated
  private TextField postCodeTf;
  @AutoGenerated
  private Label label_4;
  @AutoGenerated
  private TextArea addressLine2Tf;
  @AutoGenerated
  private Label label_8;
  @AutoGenerated
  private TextArea addressLine1Tf;
  @AutoGenerated
  private Label label_2;
  @AutoGenerated
  private TextArea descriptionTf;
  @AutoGenerated
  private Label label_5;
  @AutoGenerated
  private TextField nameTf;
  @AutoGenerated
  private Label label_1;
  @AutoGenerated
  private ComboBox statusComboBox;
  @AutoGenerated
  private Label label_21;
  @AutoGenerated
  private ComboBox typeComboBox;
  @AutoGenerated
  private Label label_19;
  @AutoGenerated
  private TextField codeTextField;
  @AutoGenerated
  private Label label_17;
  @AutoGenerated
  private ComboBox areaComboBox;
  @AutoGenerated
  private Label label_15;
  @AutoGenerated
  private ComboBox stateComboBox;
  @AutoGenerated
  private Label label_13;
  @AutoGenerated
  private ComboBox countryComboBox;
  @AutoGenerated
  private Label label_11;
  @AutoGenerated
  private Upload image_upload_1;
  @AutoGenerated
  private Label label_6;
  /**
   * The constructor should first build the main layout, set the composition
   * root and then do any custom initialization.
   * 
   * The constructor will not be automatically regenerated by the visual
   * editor.
   */
  
  private Window window;
  private StoreDTO store;
  private StoreDataProvider storeDataProvider;
  private StoreContainer storeContainer;
  List&lt;CountryDTO&gt; countries = null;
  List&lt;StoreTypeDTO&gt; storeTypeList = null;
  List&lt;AreaDTO&gt; areasList=null;
  String imageMediumUrl;
  String imageHighUrl;
  String imageLowUrl;
  private ImageUploader uploader;
  
  public NewStoreWindow() {
      buildMainLayout();
      setCompositionRoot(mainLayout);
      statusComboBox.addItem(Status.ACTIVE);
      statusComboBox.addItem(Status.INACTIVE);
      statusComboBox.setNullSelectionAllowed(false);
  
      try {
          countries = StoreDataProvider.getStoreDataProvider()
                  .getAllCountries();
      } catch (Exception e1) {
          // TODO Auto-generated catch block
          e1.printStackTrace();
      }
  
      for (CountryDTO country : countries) {
          countryComboBox.addItem(country);
  
  
      }
      if (countries != null &amp;&amp; !countries.isEmpty()) {
          countryComboBox.select(countries.get(0));
      }
      countryComboBox.setNullSelectionAllowed(false);
      CountryDTO dto=(CountryDTO)countryComboBox.getValue();
  
      try {
          areasList=StoreDataProvider.getStoreDataProvider().getAreasByCountry(dto.getId());
          areaComboBox.removeAllItems();
          for (AreaDTO area : areasList) {
              areaComboBox.addItem(area);
  
          }
      } catch (Exception e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
      }
      areaComboBox.setNullSelectionAllowed(false);
      countryComboBox.addListener(new ValueChangeListener() {
  
          @Override
          public void valueChange(ValueChangeEvent event) {
              areaComboBox.removeAllItems();
              areaComboBox.setValue(null);
              CountryDTO dto=(CountryDTO)countryComboBox.getValue();
  
              try {
                  areasList=StoreDataProvider.getStoreDataProvider().getAreasByCountry(dto.getId());
  
                  for (AreaDTO area : areasList) {
                      areaComboBox.addItem(area);
  
                  }
              } catch (Exception e) {
                  // TODO Auto-generated catch block
                  e.printStackTrace();
              }
  
  
          }
  
      });
  </code></pre>