title: extjs grid real full afterrender event?
body: <p>i am having extjs GridPanel</p>
  
  <p>when i load store:</p>
  
  <pre><code>I do Ext.getBody().mask();
  
  Grid 'afterrender' event fires first
  
  Store 'load' event fires second
  
  I attached unmask function to  store load 'event'
  </code></pre>
  
  <p>but there are few moments after that event, 
  when i see white grid (between unmask and  rows populating).</p>
  
  <p>what is the proper way to unmask on real full afterrender event?
  i mean - when all rows are rendered.</p>
  
  <p>Thanks</p>