anchor constraints: they do not play well with layouts and animations. Try the code below (adapted from the example to use the layout and animation of LRP ) and you will see that the circles keep spinning around, they never stop. I think it would be better for them to stop ;-)
	| v lbls es e1 e2 a1 a2 layout stepping|
	v := RTView new.
	lbls := RTLabel new elementsOn: #(#First #Second).
	es := RTEllipse new
		size: 30;
		borderColor: Color black;
		elementsOn: #(#source #dest).
	v
		addAll: lbls;
		addAll: es.
	es @ RTDraggable.
	es @ RTLabeled.
	e1 := RTArrowedLine new
		withContinuousCircleAttachPoint;
		color: Color black;
		edgeFrom: es first to: es second.
	v add: e1.
	e2 := RTArrowedLine new
		withContinuousCircleAttachPoint;
		color: Color black;
		edgeFrom: es second to: es first.
	v add: e2.
	a1 := RTAnchorConstraint new.
	a1 anchorShape size: 10.
	a1 guideLine color: Color red.
	a1
		element: lbls first;
		edge: e1;
		balance: 0.2;
		minDistance: 10;
		build.
	(a2 := RTAnchorConstraint new)
		element: lbls second;
		edge: e2;
		balance: 0.2;
		minDistance: 10;
		build.
	layout := RTForceBasedLayout new
					charge: -450; length: 100; 
					doNotUseProgressBar; applyOn: es; yourself.
	layout initialLayout: RTSugiyamaLayout new.	
	stepping := RTSpringLayoutStepping new 
						view: v; layout: layout;
						afterBlock: [ v canvas camera focusOnCenter].
	v addAnimation: stepping.	
	^ v