Code

using System.Drawing;
using System.Drawing.Drawing2D;

using MindFusion.Diagramming;
using MindFusion.Drawing;

using Pen = System.Drawing.Pen;


namespace OrthogonalStates
{
	/// <summary>
	/// Summary description for OrthogonalState.
	/// </summary>
	public class OrthogonalState : ContainerNode
	{
		public OrthogonalState(Diagram diagram) : base(diagram)
		{
		}

		public override void Draw(IGraphics graphics, RenderOptions options)
		{
			float dividerLineY = Bounds.Bottom - Bounds.Height / 3;
			base.Draw(graphics, options);

			Pen pen = new Pen(Color.Black, 0);
			pen.DashStyle = DashStyle.Dash;
			graphics.DrawLine(pen, Bounds.Left, dividerLineY, Bounds.Right, dividerLineY);
			pen.Dispose();
		}
	}
}

...

private void MainForm_Load(object sender, System.EventArgs e)
{
	Diagram.RegisterItemClass(typeof(OrthogonalState), "OrthogonalState", 1);

	diagramView.Behavior = Behavior.Custom;
	diagramView.CustomNodeType = typeof(OrthogonalState);
}