title: Setting fill-color in XSSFCell with Apache POI does not work
body: <p>I was trying to execute the following test (mainly copied from the <a href="http://poi.apache.org/spreadsheet/quick-guide.html#FillsAndFrills" rel="nofollow">Apache POI homepage</a>) to verify the API was working correctly. The test doesn't throw an exception, but when I look at the produced Excel file the colored cell (0,0 = A1) is in fact plain white. No color applied. The cell value has been set correctly.</p>
  
  <p>I am using <code>POI 3.9-20121203 (stable)</code>.</p>
  
  <p>What am I missing here? Why does the example not work as expected?</p>
  
  <pre><code>@Test
  public void test() throws FileNotFoundException, IOException
  {
      XSSFWorkbook wb = new XSSFWorkbook();
      XSSFSheet sheet = wb.createSheet();
      XSSFRow row = sheet.createRow(0);
      XSSFCell cell = row.createCell( 0);
      cell.setCellValue("custom XSSF colors");
  
      XSSFCellStyle style1 = wb.createCellStyle();
      style1.setFillForegroundColor(new XSSFColor(new java.awt.Color(128, 0, 128)));
      style1.setFillPattern(CellStyle.SOLID_FOREGROUND);
  
      File f = new File("test.xlsx");     
      f.delete();
  
      FileOutputStream fos = new FileOutputStream(f);     
      wb.write(fos);      
      fos.close();        
  }
  </code></pre>