Crash when using Tree Layout

[valhentai]

The WPF Showcase crash when selecting the Tree layout.
it crash in the first line of SimpleTreeLayoutAlgorithm.Compute(..) method because VertexSizes is null.

public override void Compute(CancellationToken cancellationToken)
        {
            //crash here
            Sizes = new Dictionary<TVertex, Size>( VertexSizes );

I made it work by adding VertexSizes = new Dictionary<TVertex, Size>(vertexSizes); in the constructor

public SimpleTreeLayoutAlgorithm( TGraph visitedGraph, IDictionary<TVertex, Point> vertexPositions, IDictionary<TVertex, Size> vertexSizes, SimpleTreeLayoutParameters parameters )
            : base( visitedGraph, vertexPositions, parameters )
        {
            VertexSizes = new Dictionary<TVertex, Size>(vertexSizes);
            //Contract.Requires( vertexSizes != null );
            //Contract.Requires( visitedGraph.Vertices.All( v => vertexSizes.ContainsKey( v ) ) );

        }

[panthernet]

Thanks, fixed!