Program: 66890
Project: 66890
Buggy source:
private void populateSeriesTypesList(){
  if (cbSeriesType == null) {
    return;
  }
  cbSeriesType.removeAll();
  Series series=getSeriesDefinitionForProcessing().getDesignTimeSeries();
  if (getCurrentChartType().canCombine()) {
    populateSeriesTypes(ChartUIExtensionsImpl.instance().getUIChartTypeExtensions(getContext().getClass().getSimpleName()),series,this.orientation);
  }
 else {
    String seriesName=series.getDisplayName();
    cbSeriesType.add(seriesName);
    cbSeriesType.select(0);
  }
  if (this.chartModel instanceof ChartWithAxes) {
    Axis xAxis=(((ChartWithAxes)chartModel).getAxes().get(0));
    if (xAxis.getAssociatedAxes().size() > 1) {
      String lastType=ChartCacheManager.getInstance().findSeriesType();
      Axis overlayAxis=xAxis.getAssociatedAxes().get(1);
      if (!overlayAxis.getSeriesDefinitions().isEmpty()) {
        Series oseries=(overlayAxis.getSeriesDefinitions().get(0)).getDesignTimeSeries();
        String sDisplayName=oseries.getDisplayName();
        if (lastType != null) {
          cbSeriesType.setText(lastType);
        }
 else {
          cbSeriesType.setText(sDisplayName);
        }
        String seriesName=oseries.getSeriesIdentifier().toString();
        if (seriesName.trim().length() != 0) {
          Iterator<Entry<String,Series>> itr=htSeriesNames.entrySet().iterator();
          while (itr.hasNext()) {
            Entry<String,Series> entry=itr.next();
            entry.getValue().setSeriesIdentifier(seriesName);
          }
        }
      }
      changeOverlaySeriesType();
    }
  }
}

Fixed version (ground truth):
private void populateSeriesTypesList(){
  if (cbSeriesType == null) {
    return;
  }
  if (htSeriesNames == null) {
    htSeriesNames=new Hashtable<String,Series>(20);
  }
  cbSeriesType.removeAll();
  Series series=getSeriesDefinitionForProcessing().getDesignTimeSeries();
  if (getCurrentChartType().canCombine()) {
    populateSeriesTypes(ChartUIExtensionsImpl.instance().getUIChartTypeExtensions(getContext().getClass().getSimpleName()),series,this.orientation);
  }
 else {
    String seriesName=series.getDisplayName();
    cbSeriesType.add(seriesName);
    cbSeriesType.select(0);
  }
  if (this.chartModel instanceof ChartWithAxes) {
    Axis xAxis=(((ChartWithAxes)chartModel).getAxes().get(0));
    if (xAxis.getAssociatedAxes().size() > 1) {
      String lastType=ChartCacheManager.getInstance().findSeriesType();
      Axis overlayAxis=xAxis.getAssociatedAxes().get(1);
      if (!overlayAxis.getSeriesDefinitions().isEmpty()) {
        Series oseries=(overlayAxis.getSeriesDefinitions().get(0)).getDesignTimeSeries();
        String sDisplayName=oseries.getDisplayName();
        if (lastType != null) {
          cbSeriesType.setText(lastType);
        }
 else {
          cbSeriesType.setText(sDisplayName);
        }
        String seriesName=oseries.getSeriesIdentifier().toString();
        if (seriesName.trim().length() != 0) {
          Iterator<Entry<String,Series>> itr=htSeriesNames.entrySet().iterator();
          while (itr.hasNext()) {
            Entry<String,Series> entry=itr.next();
            entry.getValue().setSeriesIdentifier(seriesName);
          }
        }
      }
      changeOverlaySeriesType();
    }
  }
}