title: Trying to work with down() method from ExtJS 4.2.1
body: <p>I am trying to find a specific element from my page using ExtJS 4 so I can do modifications on it.
  I know its id so it should not be a problem BUT</p>
  
  <p>-I tried Ext.getCmp('theId') and it just return me <code>undefined</code></p>
  
  <p>-I tried to use down('theId') method by passing through the view and I still get a <code>null</code>response.</p>
  
  <p>As I know the id of the element I tried again the two methods by setting manually the id and it didn't work neither.</p>
  
  <p>Do these two methods not function?</p>
  
  <p>How should I do?</p>
  
  <p>Here is the concerned part of the code :</p>
  
  <pre><code>listeners: {
                  load: function(node, records, successful, eOpts) {
                      var ownertree = records.store.ownerTree;
                      var boundView = ownertree.dockedItems.items[1].view.id;
                      var generalId = boundView+'-record-';
                      // Add row stripping on leaf nodes when a node is expanded
                      //
                      // Adding the same feature to the whole tree instead of leaf nodes
                      // would not be much more complicated but it would require iterating
                      // the whole tree starting with the root node to build a list of
                      // all visible nodes. The same function would need to be called
                      // on expand, collapse, append, insert, remove and load events.
                      if (!node.tree.root.data.leaf) {
                          // Process each child node
                          node.tree.root.cascadeBy(function(currentChild) {
                              // Process only leaf
                              if (currentChild.data.leaf) {
                                  var nodeId = ""+generalId+currentChild.internalId;
                                  var index = currentChild.data.index;
                                  if ((index % 2) == 0) {
                                      // even node
                                      currentChild.data.cls.replace('tree-odd-node', '')
                                      currentChild.data.cls = 'tree-even-node';
                                  } else {
                                      // odd node
                                      currentChild.data.cls.replace('tree-even-node', '')
                                      currentChild.data.cls = 'tree-odd-node';
                                  }
                                  // Update CSS classes
                                  currentChild.triggerUIUpdate();
                                  console.log(nodeId);
                                  console.log(ownertree.view.body);
                                  console.log(Ext.getCmp(nodeId));
                                  console.log(Ext.getCmp('treeview-1016-record-02001001'));
                                  console.log(ownertree.view.body.down(nodeId));
                                  console.log(ownertree.view.body.down('treeview-1016-record-02001001'));
                              }
                          });
                      }
                  }
  </code></pre>
  
  <p>You can see my console.log at the end.
  Here is what they give me on the javascript console (in the right order):</p>
  
  <pre><code>treeview-1016-record-02001001
  </code></pre>
  
  <p>The precise id I am looking for. And I also try manually in case...</p>
  
  <pre><code>h {dom: table#treeview-1016-table.x-treeview-1016-table x-grid-table, el: h, id: "treeview-1016gridBody", $cache: Object, lastBox: Object…}
  </code></pre>
  
  <p>I checked every configs of this item and its dom and it is exactly the part of the dom I am looking for, which is the view containing my tree. The BIG parent</p>
  
  <p>And then:</p>
  
  <pre><code>undefined
  undefined
  null
  null
  </code></pre>
  
  <p>Here is the item I want to access:</p>
  
  <pre><code>&lt;tr role="row" id="treeview-1016-record-02001001" ...&gt;
  </code></pre>
  
  <p>And I checked there is no id duplication anywhere...</p>
  
  <p>I asked someone else who told me these methods do not work. The problem is I need to access this item to modify its cls.</p>
  
  <p>I would appreciate any idea.</p>