title: extjs rowEditing plugin startEdit always return false
body: <p>Here is my code to insert an editable item to grid</p>
  
  <pre><code>var grid = button.up('#gpDiabeticsSelfAssessment'),
  store = grid.getStore(),
  record = Ext.create('HMETRIX.model.DiabeticsSelfAssessment', {}),
  plugin = grid.editingPlugin;
  store.insert(0,record);
  plugin.startEdit(record,0);
  </code></pre>
  
  <p>It's not working. Not even double clicking the row enables editing.</p>
  
  <p>Whats wrong with this.</p>