Hi,

The Arrange methods do not change Diagram.Bounds; perhaps you are calling ResizeToFit after each Arrange? Anyway you can define your own commands to keep track of Bounds and other Diagram properties, e.g.

public class DiagramState : Command
{
	public DiagramState(Diagram diagram, string title) : base(title)
	{
		this.diagram = diagram;
		oldBounds = diagram.Bounds;
	}

	RectangleF oldBounds, newBounds;
	Diagram diagram;

	protected override void Execute(bool undoEnabled)
	{
		newBounds = diagram.Bounds;
	}

	protected override void Undo()
	{
		diagram.Bounds = oldBounds;
	}

	protected override void Redo()
	{
		diagram.Bounds = newBounds;
	}
}
 

and use it like this:

DiagramState diagramState = new DiagramState(diagram, "Bounds changed");
diagram.ResizeToFitItems(5);
diagram.ExecuteCommand(diagramState);

If you are always calling ResizeToFitItems after Arrange, you might prefer to do that as well in the ActionUndone and ActionRedone event handlers when they are raised for layout commands, instead of using a custom command.

I hope that helps,
Stoyan