title: How to use bookmarks and DisableControls
body: <p>Is it possible to do</p>
  
  <pre><code>dataset.DisableControls
  Bookmark1 := dataset.Bookmark;
  { do someting............. }
  dataset.enableControls;
  dataset.Bookmark := Bookmark1;
  dataset.FreeBookmark(Bookmark1);
  </code></pre>
  
  <p>Let say getting the total of a TDBGrig.</p>