Code

private void diagramView_MouseMove(object sender, MouseEventArgs e)
{
	PointF mousePos = diagramView.ClientToDoc(e.Location);
	DiagramLink link = diagram.GetLinkAt(mousePos, 3);
	if (link != null && link.Selected && (
		Utilities.Distance(link.StartPoint, mousePos) <= diagram.AdjustmentHandlesSize ||
		Utilities.Distance(link.EndPoint, mousePos) <= diagram.AdjustmentHandlesSize))
	{
		diagramView.OverrideCursor = Cursors.Hand;
	}
	else
	{
		diagramView.OverrideCursor = null;
	}
}