Determine when a node is dropped onto a diagram


I'm trying to determine what event etc. I should handle to determine when a node is dragged off a palette and dropped onto a GoXam diagram?
I want to know when the node is actually dropped (so I can display a dialog).
It appears that a new node is added to the collection which Model.NodesSource is bound to as soon as the node is dragged over the diagram (rather than when the node is actually dropped). Therefore, if I have a ModelChanged handler and handle the 'AddedNode' change, this occurs as soon as the node is dragged over the diagram.
So far, the only way I've found to sort of do this is to handle the ExternalCopy change and run through the list of edits in the transaction looking for an AddedNode one.
Is this the best way to do this, or is there a preferred solution.
Or is it possible to do something so that the NodesSource collection is only added to when the node is actually dropped.

I think you want to implement a Diagram.ExternalObjectsDropped event handler.


I managed to get what I wanted working using this.