title: WPF Datagrid: SelectionChanged event isn't raised when SelectionUnit="Cell"
body: <p>I'm using the WPF toolkit datagrid. I have it set to <strong>SelectionUnit="Cell"</strong> and <strong>SelectionMode="Extended"</strong>.</p>
  
  <p>The SelectionChanged event is never raised!</p>
  
  <p>It works fine when the SelectionUnit is set to FullRow.</p>
  
  <p>Am I Missing something?</p>
  
  <p>BTW, the reason I need it is since I'm trying to create an Attached Property to help me bind the SelectedCells to my ViewModel.</p>