title: how to use row-editor plugin for treeGrid
body: <p>i have a treegrid and i need to make it as editorGrid.</p>
  
  <p>My treegrid is</p>
  
  <pre><code>var tree = new Ext.ux.tree.TreeGrid({
      title: 'Core Team Projects',
       height: 500,
      renderTo: Ext.getBody(),
        autoLoad:false,
      plugins: [editor],
        columns:[
          {
          header: 'Name',
          dataIndex: 'name',
          width: 230
      },{
          header: 'length',
          width: 150,
          sortType: 'asFloat',
          dataIndex: 'length'
      },{
          header: 'size',
          width: 150,
          sortType: 'asFloat',
          dataIndex: 'size'
      },{
          header: 'dataType',
          width: 150,
          dataIndex: 'dataType'
      },{
          header: 'extName',
          width: 150,
          dataIndex: 'extName'
      },{
          header: 'overlay',
          width: 150,
          dataIndex: 'overlay'
      },{
          header: 'qualified',
          width: 150,
          dataIndex: 'qualified'
      }],
      loader: myTreeLoader
  </code></pre>
  
  <p>});</p>
  
  <p>and the editor which i used is </p>
  
  <pre><code>var editor = new Ext.ux.grid.RowEditor({
      saveText: 'Save',
      errorSummary : true,
      monitorValid: true,
      clicksToEdit: 1,
      // floating: true,
      shadow: true,
      layout: 'hbox',
      cls: 'x-small-editor',
      buttonAlign: 'center',
      baseCls: 'x-row-editor',
      elements: 'header,footer,body',
      frameWidth: 5,
      buttonPad: 3,
      focusDelay: 250,
      cancelText: 'Cancel',
      //commitChangesText: 'You need to Update or Cancel your changes',
      // errorText: 'Errors',
  
      defaults: {
          normalWidth: true
      }
  });
  </code></pre>
  
  <p>it gives an error "Object doesn't support this property or method"</p>
  
  <p>Could Someone pls give a solution</p>