Code

private void diagramView_MouseDown(object sender, MouseEventArgs e)
{
	if ((ModifierKeys & Keys.Shift) != 0)
	{
		PointF mousePosition = diagramView.ClientToDoc(e.Location);
		TableNode table = diagram.GetNodeAt(mousePosition) as TableNode;
		if (table != null)
		{
			int row = 0, col = 0;
			if (table.CellFromPoint(mousePosition, ref row, ref col))
			{
				string text = table[col, row].Text;
				if (diagram.Interaction != null)
					diagram.Interaction.CancelNow();
				DoDragDrop(text, DragDropEffects.Copy);
			}
		}
	}
}