title: Nested grid with rowExpander creating issues
body: <p>I am using Extjs3.2 nested grid with rowExpander.</p>
  
  <p>In my case everything working fine..
  but whenever i click on nth row in child grid the parent grid's nth row is also getting selected.
  How to Stop this...Please Help??</p>
  
  <p>My Code</p>
  
  <pre><code> var expander = new Ext.ux.grid.RowExpander({
                   expandOnDblClick : false,
                   tpl : new Ext.Template('&lt;div id="NestedGridRow-{id}"&gt;&lt;/div&gt;'),
  
                   renderer: function(v, p, record) {
                          if (record.get('cmaStatus') == 'G') {
                              p.cellAttr = 'rowspan="2"';
                              return '&lt;div class="x-grid3-row-expander"&gt;&lt;/div&gt;';
                          } 
              },
  
  
              });
  
  
  
              expander.on('expand', expandedRow);
  
              function expandedRow(obj, record, body, rowIndex){
                  //absId parameter for the http request to get the absence details.
  
  
                  //Use Id to give each grid a unique identifier. The Id is used in the row expander tpl.
                  //and in the grid.render("ID") method.
  
                  var row = "NestedGridRow-" + record.get("id");
                  var id2 = "mygrid-" +record.get("id"); 
  
                  sapid_para = record.get('sapid');
                 //Create the nested grid.         
                 var gridX = new Ext.grid.GridPanel({
                     id:'nestedGrid',
                      store: storenested,
                      //stripeRows: true,
                      columns: [
  
  
                          {
                              header : "CMA Date",
                              width : 120,
                              sortable : true,
                              dataIndex : 'cmaDate',
  
                          },
                          {
                              header : "Source Model",
                              width : 120,
                              sortable : true,
                              dataIndex : 'sourceModel',
  
                          },
  
                          {
                              header : "Remarks",
                              width : 390,
                              sortable : true,
                              dataIndex : 'remarks',
  
                          }],
                  height: 120,
                  id: id2,
                  plugins : [editor],
                  renderTo: row,
                  stripeRows:true,
                  listeners: {
                      render: function(gridX) {
                          gridX.getView().el.select('.x-grid3-header').setStyle('display', 'none');
                      },
  
                      rowclick : function(grid,rowIndex,e) {
                          alert(rowIndex);                                       
                          }
  
  
                      },
  
                                  });  
                  gridX.render(row);
  
  
                  //Ext.getCmp('grid_lineage').getStore().load({params:{start:0, limit:10}});
                  storenested.load({params:{start:0, limit:10}});
  </code></pre>