title: Table propertyId value is null when using setCellStyleGenerator
body: <p>I am new to Vaadin but do have some Java Swing experience.</p>
  
  <p>I am attempting to use table.setCellStyleGenerator to set the colour of a particular cell with the column heading "Name".</p>
  
  <p>I am working off an example in vaadin book:</p>
  
  <pre><code>Table table = new Table("Table with Cell Styles");
      table.addStyleName("checkerboard");
  
      table.addContainerProperty("0",String.class,null,"Name", null,  null);
      table.addContainerProperty("1",String.class,null,"Surname", null,  null);
      table.addContainerProperty("2",Date.class,null,"Date.", null,  null);
      table.addContainerProperty("3",Integer.class,null,"Required.", null,  null);
      table.addContainerProperty("4",Integer.class,null,"Complete", null,  null);
  
  
      table.addContainerProperty("5",String.class,null,"Cakes", null,  null);
      table.addContainerProperty("6",Integer.class,null,"Cake Quantity", null,  null);
      table.addContainerProperty("7",String.class,null,"Status", null,  null);
      table.addContainerProperty("8",TextField.class,null,"Notes", null,  null);
  </code></pre>
  
  <p>I have populated my table as follows:</p>
  
  <pre><code>/* Add a few items in the table. */
      table.addItem(new Object[] {
          "Nicolaus","Copernicus",new Date("21/05/2011"), new Integer(1473), new Integer(1), "Cake",  new Integer(1473), "cakestatus", commentsField }, new Integer(3)); 
  </code></pre>
  
  <p>I am able to communicate with my stylesheet  but when I try the following:</p>
  
  <pre><code>table.setCellStyleGenerator(new Table.CellStyleGenerator() {
          public String getStyle(Object itemId, Object propertyId) {
              int row = ((Integer)itemId).intValue();
            int col = Integer.parseInt((String)propertyId);
  
  
           System.out.println("COL:"+ col);  
              // The first column.
            if (col == 0)
               return "rowheader";
                                    .... 
  </code></pre>
  
  <p>[b]PropertyId [/b]appears null. </p>
  
  <p>and Tomcat spews the following:</p>
  
  <blockquote>
    <p>SEVERE: Terminal error:<br>
    java.lang.NumberFormatException: null<br>
        at java.lang.Integer.parseInt(Unknown Source)</p>
  </blockquote>
  
  <p>I'm pretty sure I'm making some beginners error. </p>
  
  <p>Btw my styles.css is accessed as follows:</p>
  
  <pre><code>mainWindow.setTheme("colouredCells");
  
  /* Create the table with a caption. */
  Table table = new Table("Table with Cell Styles");
  table.addStyleName("checkerboard"); 
  </code></pre>
  
  <p>and the CSS contains the following:</p>
  
  <pre><code>@import url(../colouredCells/styles.css);
  /* Using the old default theme (runo) as the basis for now */
  
  
  
  
  
  /* Center the text in header. */
  .v-table-header-cell {
      text-align: center;
  }
  
  /* Basic style for all cells. */
  .v-table-checkerboard .v-table-cell-content {
      text-align: center;
      vertical-align: middle;
      padding-top: 12px;
      width: 20px;
      height: 28px;
  }
  
  /* Style specifically for the row header cells. */
  .v-table-cell-content-rowheader {
      background: #E7EDF3
       url(../default/table/img/header-bg.png) repeat-x scroll 0 0;
  }
  
  /* Style specifically for the "white" cells. */
  .v-table-cell-content-white {
      background: white;
      color: black;
  }
  
  /* Style specifically for the "black" cells. */
  .v-table-cell-content-black {
      background: #60497b;
      color: white;
  }
  </code></pre>