Index: branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionAfterCrossoverOperator.cs
===================================================================
--- branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionAfterCrossoverOperator.cs	(revision 10890)
+++ branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionAfterCrossoverOperator.cs	(revision 10897)
@@ -30,5 +30,5 @@
   public class SymbolicDataAnalysisExpressionAfterCrossoverOperator : AfterCrossoverOperator<ISymbolicExpressionTree> {
     public override IOperation Apply() {
-      var childVertex = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph[ChildParameter.ActualValue];
+      var childVertex = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph.GetVertex(ChildParameter.ActualValue);
       var arcs = childVertex.InArcs.ToList();
       var nodes0 = (List<ISymbolicExpressionTreeNode>)arcs[0].Data;
Index: branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionAfterManipulatorOperator.cs
===================================================================
--- branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionAfterManipulatorOperator.cs	(revision 10890)
+++ branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionAfterManipulatorOperator.cs	(revision 10897)
@@ -40,5 +40,5 @@
 
     public override IOperation Apply() {
-      var vChild = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph[ChildParameter.ActualValue];
+      var vChild = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph.GetVertex(ChildParameter.ActualValue);
       var nodesBefore = (List<ISymbolicExpressionTreeNode>)vChild.InArcs.First().Data;
       var nodesAfter = ChildParameter.ActualValue.IterateNodesPrefix().ToList();
Index: branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionBeforeCrossoverOperator.cs
===================================================================
--- branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionBeforeCrossoverOperator.cs	(revision 10890)
+++ branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionBeforeCrossoverOperator.cs	(revision 10897)
@@ -30,5 +30,5 @@
       var result = base.Apply(); // the base operator will add the child to the graph before the actual crossover operation takes place
       var parents = ParentsParameter.ActualValue.ToList();
-      var childVertex = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph[parents[0]]; // use the parent since it is actually the child before crossover (and the ChildParameter doesn't have a value yet)
+      var childVertex = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph.GetVertex(parents[0]); // use the parent since it is actually the child before crossover (and the ChildParameter doesn't have a value yet)
       var arcs = childVertex.InArcs.ToList();
 
Index: branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionBeforeManipulatorOperator.cs
===================================================================
--- branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionBeforeManipulatorOperator.cs	(revision 10890)
+++ branches/HeuristicLab.EvolutionTracking/HeuristicLab.Problems.DataAnalysis.Symbolic/3.4/Tracking/SymbolicDataAnalysisExpressionBeforeManipulatorOperator.cs	(revision 10897)
@@ -30,5 +30,5 @@
       var result = base.Apply(); // add the vertex in the genealogy graph
 
-      var vChild = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph[ChildParameter.ActualValue];
+      var vChild = (IGenealogyGraphNode<ISymbolicExpressionTree>)GenealogyGraph.GetVertex(ChildParameter.ActualValue);
       var vClone = vChild.Parents.Last();
       vChild.InArcs.First().Data = vClone.Content.IterateNodesPrefix().ToList();
