title: Reload DataGrid with DataSource is too slow only when DataGrid is on the current active tab
body: <p>I have TabControl and DataGrid with DataSource in one of the tabs . 
  When I "Reload" my DataSource (pull data from DataBase, clear DataSource and fill it again with the objects), it is too slow (a half an hour or more, for 65000 records) if current active Tab is tab where is the DataGreed. If some other Tab is active it takes 2 minutes.</p>
  
  <p>I just do test with "visible=false" for DataGrid and it work fast, as normal, but it is not an option, I wanna that client see DataGreed during its reload. </p>
  
  <p>It looks as the DataGrid does "something" (which slow down) after adding every single row in DataSource.</p>
  
  <p>AutoSizeColumnsMode is already None</p>
  
  <p>Is there any trick how I can solve this problem? any advice is appreciated.</p>