title: Add row expander for second column in grid - extjs4
body: <p>I am very new for extjs 4.I am facing one problem.Hope somebody will help.
      I am having grid.I have added row expand in that grid.
      Here is my code :</p>
  
  <pre><code>Ext.define('Citi.iv.view.portfolio.PositionsLiabilitiesGrid', {
  extend : 'Ext.grid.Panel',
  requires:['Ext.ux.RowExpander'],
  alias : 'widget.positionsliabilitiesgrid',
  headerHeight:80,
  itemId : 'financialPositionsassetGrid',
  margin: '0 0 10px 0',
  flex : 1,
  cls : 'grey_alt_grid',
  scroll : 'vertical',
  autoScroll: true,
  emptyText : 'No Data Found',
  plugins: [{
          ptype: 'rowexpander',
          rowBodyTpl : [
              '&lt;p&gt;&lt;b&gt;Render data here&lt;/b&gt;&lt;/p&gt;&lt;br&gt;'
  
          ]
      }],
  collapsible: true,
  columns : [{
      header : 'Account Descriptions',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex : 'account_description'
  }, {
      header : 'Account',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex : 'account'
  }, {
      header : 'Amount You Own',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex :'amount_you_own',
  }, {
      header : 'Interest Rate',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex : 'interest_rate'
  }, {
      header : 'Next Payment',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex : 'next_payment'
  }, {
      header : 'Payment Due Date',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex : 'payment_due_date'
  }, {
      header : 'Interest Paid',
      flex : 1,
      xtype : 'gridcolumn',
      hideable: false,
      dataIndex : 'interest_paid'
  }]
  </code></pre>
  
  <p>});</p>
  
  <p>I am getting expand on 1st column.I want add the expand icon on second column. Any idea?</p>