I have user data tagged to a ShapeNode. I need to get this data upon the node selection; but the tag is null in the selectionChanged event handler.

private void diagram_SelectionChanged(object sender, EventArgs e)
{
    foreach (ShapeNode node in diagram.Selection.Nodes)
    {
        // My tag is always null here?

        if (node.Tag != null)
        {
            // ...
        }
    }
}