title: how to set loading mask to whole web page, not the grid panel only
body: <p><img src="https://i.stack.imgur.com/Mqb2S.jpg" alt="enter image description here"></p>
  
  <p>I have a tab panel, while loading the grid panel, user able to switch then tabs and toolbar menu.
  Any idea to let user disable whole page website, after the tab content loaded. User only able to access other components.</p>
  
  <p>This is how I set the grid panel when loading the data store:</p>
  
  <p><code>grid.setLoading(true);</code></p>
  
  <p>While page loaded grid, grid only appear loading mask, how to set while tab's page are loading then set a mask. Not when page loaded the grid only start the mask and wait the data store get the data.</p>
  
  <p>vehicle manage is my default tab page.<br>
  What I mean is when the user key in the url like <code>http://mywebsite.com</code> then having a mask, wait until the vehicle manage page are loaded all, then unmask the whole page. when user click driver manager, then mask the whole page again, wait until all page are loaded only unmask it. How to do it?</p>