title: JFreeChart DateTickUnit does not work properly
body: <p>I am giving user change ability  to filter graph result.For example user can select to show results for 2 day.Then TimeUnitType  is day, timeAmount is 2.But This is not work properly.For this case,  it must be only 2 thick unit.Date related to first day must be shown in related tick unit. Another data related to day 2 must be shown in second thick unit.</p>
  
  <p>For example by default 1 day is selected.It shows a black line under domain axis.</p>
  
  <p><img src="https://i.stack.imgur.com/E08CM.jpg" alt="Domain Axis view"></p>
  
  <p>I am selecting 1 month interval .DomainAxis does not show any thick.</p>
  
  <pre><code>    private void customizeGraphView(JFreeChart chart, TimeUnitType timeUnit, Integer timeAmount) {
      CombinedRangeXYPlot combinedPlot = (CombinedRangeXYPlot) chart.getPlot();
      @SuppressWarnings("unchecked")
      /** read 2 subplot*/
      List&lt;XYPlot&gt; subPlots = combinedPlot.getSubplots();
      for (int plotIndex = 0; plotIndex &lt; subPlots.size(); plotIndex++) {
          /** get plot */
          XYPlot plot = subPlots.get(plotIndex);
          plot.setDomainGridlinesVisible(false);
          // plot.setRangeGridlinesVisible(false);
          XYItemRenderer itemRenderer = plot.getRenderer();
          /** if line and shape rendere */
          if (itemRenderer instanceof StandardXYItemRenderer) {
              StandardXYItemRenderer renderer = (StandardXYItemRenderer) itemRenderer;
              /** show shapes in time series */
              renderer.setBaseShapesVisible(true);
              /** fill shapes in time series */
              renderer.setBaseShapesFilled(true);
              renderer.setBaseFillPaint(Color.BLACK);
              // addItemLabels(renderer);
          }
          /** change DateAxis specific vaues */
          DateAxis dateAxis = (DateAxis) plot.getDomainAxis();
          /** change Date Axis Time Unit format */
          dateAxis.setTickLabelsVisible(true);
          /** add severity bar */
          if (plotIndex == 0) {
              dateAxis.setAutoRange(true);
              if(getFirstGraphMinRange() != null &amp;&amp; getFirstGraphMaxRange() != null)
              {
                  dateAxis.setRange(getHistoryGraphMinRange(), getHistoryGraphMaxRange());
                  dateAxis.setTickUnit(new DateTickUnit(getTickUnitType(timeUnit), timeAmount));
              }
          } else {
              dateAxis.setDateFormatOverride(new SimpleDateFormat("HH:mm", Locale.getDefault()));
              dateAxis.setRange(getSecondGraphMinRange(), getSecondGraphMaxRange());
              dateAxis.setTickUnit(new DateTickUnit(DateTickUnitType.MINUTE, 5));
          }
      }
  
  }
  
      /**
   * @param timeUnit
   * @return
   */
  private DateTickUnitType getTickUnitType(TimeUnitType timeUnit) {
      DateTickUnitType unitType = null;
      switch (timeUnit) {
      case HOUR:
          unitType = DateTickUnitType.HOUR;
      break;
      case DAY:
          unitType = DateTickUnitType.DAY;
      break;
      case MONTH:
          unitType = DateTickUnitType.MONTH;
      break;
      default:
      break;
      }
      return unitType;
  }
  </code></pre>