Code

public class MyBehavior : LinkTablesBehavior
{
	public MyBehavior(DiagramView view) : base(view)
	{
	}

	public override CursorHint SetMouseCursor(PointF point, out bool startInteraction)
	{
		CursorHint cursor = base.SetMouseCursor(point, out startInteraction);

		TableNode table = Diagram.GetNodeAt(point) as TableNode;
		if (table != null)
		{
			int row = 0, col = 0;
			if (table.CellFromPoint(point, ref row, ref col))
			{
				if (col == 0)
				{
					DiagramView.Cursor = Cursors.Arrow;
					cursor = CursorHint.DontChange;
				}
			}
		}

		return cursor;
	}
}