or below the selected node.
</p><p>
Now that you can determine what's being dragged and where the user proposes to drag it to, you
can start building logic to control the drag operation.  
</p><ol><li>To conditionally enable/disable a drop,
use the <span class="code">OLEDragOver</span> event and set the <span class="code">AllowedEffects</span>
to tell the control what can be done.  (<span class="code">AllowedEffects</span> can be set to one of
the <span class="code">OLEDropEffectConstants</span> provided in