title: events for docked items in ext js
body: <p>i am a noob in ext js and stuck with a problem.<br>
   i have created an app 
  this is the <code>init</code> function of my controller.</p>
  
  <pre><code>init: function () {
          console.log('initialized filesystem controller');
          this.control({
              'filesystemtree': {
                  itemdblclick: this.OpenFile,
                  select: this.NodeSelected
              },
              'filesystemtree filesystemmenu button[text="Delete"]': {
                  click:this.DeleteButtonClicked
              }
          });
      }
  </code></pre>
  
  <p>and this is the view with <code>xtype : 'filesystemtree'</code></p>
  
  <pre><code>Ext.define('IDE.view.fileSystem.List', {
      extend: 'Ext.tree.Panel',
      alias: 'widget.filesystemtree',
      title: 'Navigation2',
      store: 'FileSystems',
      rootVisible: 'false',
      dockedItems: [{
          xtype:'filesystemmenu',
          dock:'top'
      }],
      initComponent: function () {
          console.log('file system tree initializing');
          this.callParent(arguments);
      }
  })
  </code></pre>
  
  <p>and this is the view with <code>xtype:filesystemmenu</code> docked to <code>filesystemtree</code></p>
  
  <pre><code>Ext.define('IDE.view.fileSystem.FileSystemMenu', {
      extend: 'Ext.toolbar.Toolbar',
      alias: 'widget.filesystemmenu',
      items: [
          {
              xtype: 'splitbutton',
              text: 'Menu',
              menu: new Ext.menu.Menu({
                  items: [
                          {
                              text: 'Delete'
                          },
                          {
                              text: 'Copy'
                          },
                          {
                              text: 'Paste'
                          },
                          {
                              text: 'Cut'
                          },
                          {
                              name: 'Rename',
                              xtype: 'textfield',
                              emptyText: 'Enter text to rename'
                          }
                      ]
              })
          },
          {
              text: 'Add Item',
              id:'FSAddItemButton'
          },
          '-&gt;',
          {
              xtype: 'box',
              id: 'fileSystemNodeNameLabel'
          }
      ]
  })
  </code></pre>
  
  <p>but in the controller im unable to attach a click event to the delete button present in the <code>filesystemmenu</code> which itself is present as a docked item to the <code>filesystemtree</code>.
  basically this line in the controller aint working.</p>
  
  <pre><code>'filesystemtree filesystemmenu button[text="Delete"]': {
                  click:this.DeleteButtonClicked
              }
  </code></pre>
  
  <p>what am i doing wrong?</p>