title: Allow focus change in RadGridView when a cell has an error
body: <p>I am using the <code>INotifyDataError</code> interface to add errors to an object.  If the object is displayed in a RadGridView, the user is prevented from changing the focus from current cell if that property has an error.  I would like to allow this.</p>
  
  <p>For example, let's say I have</p>
  
  <pre><code>class Foo
  {
      public string A { get; set; }
      public bool B { get; set; }
  }
  </code></pre>
  
  <p>Now, let's say my validation logic is</p>
  
  <pre><code>if (A == "x" &amp;&amp; B == false)
  {
      //Add error to A
  }
  </code></pre>
  
  <p>Now, let's say this is a new record where <code>A = null, B = false</code>.  If the user enters "x" for A, the record will become invalid and the user will be unable to leave that cell.  This prevents the user from changing B to true which will remove the error.</p>
  
  <p>I want to display the error on the cell, but still allow the user to change focus away from that cell.  Is there any way to change the behavior of the RadGridView to allow this?</p>