/** Loads combo choices fromt he platform and from PDE core preferences */
  private void initializeChoices() {
    IEclipsePreferences node = new InstanceScope().getNode(PDECore.PLUGIN_ID);

    fOSChoices = new TreeSet<String>();
    String[] os = Platform.knownOSValues();
    for (int i = 0; i < os.length; i++) {
      fOSChoices.add(os[i]);
    }
    String pref = node.get(ICoreConstants.OS_EXTRA, EMPTY_STRING);
    if (!EMPTY_STRING.equals(pref)) {
      addExtraChoices(fOSChoices, pref);
    }

    fWSChoices = new TreeSet<String>();
    String[] ws = Platform.knownWSValues();
    for (int i = 0; i < ws.length; i++) {
      fWSChoices.add(ws[i]);
    }
    pref = node.get(ICoreConstants.WS_EXTRA, EMPTY_STRING);
    if (!EMPTY_STRING.equals(pref)) {
      addExtraChoices(fWSChoices, pref);
    }

    fArchChoices = new TreeSet<String>();
    String[] arch = Platform.knownOSArchValues();
    for (int i = 0; i < arch.length; i++) {
      fArchChoices.add(arch[i]);
    }
    pref = node.get(ICoreConstants.ARCH_EXTRA, EMPTY_STRING);
    if (!EMPTY_STRING.equals(pref)) {
      addExtraChoices(fArchChoices, pref);
    }

    fNLChoices = new TreeSet<String>();
    String[] nl = LocaleUtil.getLocales();
    for (int i = 0; i < nl.length; i++) {
      fNLChoices.add(nl[i]);
    }
    pref = node.get(ICoreConstants.NL_EXTRA, EMPTY_STRING);
    if (!EMPTY_STRING.equals(pref)) {
      addExtraChoices(fNLChoices, pref);
    }
  }
 public static Choice[] getWSChoices() {
   return getKnownChoices(Platform.knownWSValues());
 }