se
      AllowedEffects = vbDropEffectMove
   End If
   '
End Sub
</pre><p>
The second is handled by creating a drag location verification function and calling
it during the <span class="code">OLEDragOver</span> event:
</p><pre>
Private Sub tvwDrag_OLEDragOver( _
      Data As DataObject, _
      Effect As Long, _
      Button As Integer, _
      Shift As Integer, _
      x As Single, y As Single, _
      State As Integer)
   
   ' Check if we're attempting to make something a child of
   ' itself:
   Dim n