Index: /branches/DataPreprocessing/HeuristicLab.DataPreprocessing.Views/3.3/DataPreprocessingView.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.DataPreprocessing.Views/3.3/DataPreprocessingView.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.DataPreprocessing.Views/3.3/DataPreprocessingView.cs	(revision 10922)
@@ -66,6 +66,5 @@
           new ScatterPlotContent(chartLogic),
           new CorrelationMatrixContent(problemData),
-          new DataCompletenessChartContent(dataGridLogic, searchLogic)
-          //new DataCompletenessChartContent(dataCompletenessLogic),
+          new DataCompletenessChartContent(dataGridLogic, searchLogic),
           
           new FilterContent(filterLogic),
Index: /branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/ProblemDataCreator.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/ProblemDataCreator.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.DataPreprocessing/3.3/ProblemDataCreator.cs	(revision 10922)
@@ -36,5 +36,5 @@
 
     private IEnumerable<string> InputVariables { get { return context.Data.VariableNames; } }
-    private IEnumerable<ITransformation> Transformations { get { return context.Data.Transformations; } }
+    private IList<ITransformation> Transformations { get { return context.Data.Transformations; } }
 
     public ProblemDataCreator(IPreprocessingContext context) {
Index: /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis.Trading/3.4/ProblemData.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis.Trading/3.4/ProblemData.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis.Trading/3.4/ProblemData.cs	(revision 10922)
@@ -1628,6 +1628,6 @@
     }
 
-    public ProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, string targetVariable, IEnumerable<ITransformation> transformations = null)
-      : base(dataset, allowedInputVariables, transformations ?? Enumerable.Empty<ITransformation>()) {
+    public ProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, string targetVariable, IList<ITransformation> transformations = null)
+      : base(dataset, allowedInputVariables, transformations ?? new List<ITransformation>()) {
       var variables = InputVariables.Select(x => x.AsReadOnly()).ToList();
       Parameters.Add(new ConstrainedValueParameter<StringValue>(PriceChangeVariableParameterName, new ItemSet<StringValue>(variables), variables.First(x => x.Value == targetVariable)));
Index: /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Classification/ClassificationProblemData.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Classification/ClassificationProblemData.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Classification/ClassificationProblemData.cs	(revision 10922)
@@ -292,6 +292,6 @@
     }
 
-    public ClassificationProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, string targetVariable, IEnumerable<ITransformation> transformations = null)
-      : base(dataset, allowedInputVariables, transformations ?? Enumerable.Empty<ITransformation>()) {
+    public ClassificationProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, string targetVariable, IList<ITransformation> transformations = null)
+      : base(dataset, allowedInputVariables, transformations ?? new List<ITransformation>()) {
       var validTargetVariableValues = CheckVariablesForPossibleTargetVariables(dataset).Select(x => new StringValue(x).AsReadOnly()).ToList();
       var target = validTargetVariableValues.Where(x => x.Value == targetVariable).DefaultIfEmpty(validTargetVariableValues.First()).First();
Index: /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Clustering/ClusteringProblemData.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Clustering/ClusteringProblemData.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Clustering/ClusteringProblemData.cs	(revision 10922)
@@ -21,5 +21,4 @@
 
 using System.Collections.Generic;
-using System.Linq;
 using HeuristicLab.Common;
 using HeuristicLab.Core;
@@ -88,6 +87,6 @@
     }
 
-    public ClusteringProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, IEnumerable<ITransformation> transformations = null)
-      : base(dataset, allowedInputVariables, transformations ?? Enumerable.Empty<ITransformation>()) {
+    public ClusteringProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, IList<ITransformation> transformations = null)
+      : base(dataset, allowedInputVariables, transformations ?? new List<ITransformation>()) {
     }
   }
Index: /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/DataAnalysisProblemData.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/DataAnalysisProblemData.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/DataAnalysisProblemData.cs	(revision 10922)
@@ -53,6 +53,6 @@
       get { return (IFixedValueParameter<IntRange>)Parameters[TestPartitionParameterName]; }
     }
-    public IFixedValueParameter<ReadOnlyItemCollection<ITransformation>> TransformationsParameter {
-      get { return (IFixedValueParameter<ReadOnlyItemCollection<ITransformation>>)Parameters[TransformationsParameterName]; }
+    public IFixedValueParameter<ReadOnlyItemList<ITransformation>> TransformationsParameter {
+      get { return (IFixedValueParameter<ReadOnlyItemList<ITransformation>>)Parameters[TransformationsParameterName]; }
     }
     #endregion
@@ -120,5 +120,5 @@
     private void AfterDeserialization() {
       if (!Parameters.ContainsKey(TransformationsParameterName)) {
-        Parameters.Add(new FixedValueParameter<ReadOnlyItemCollection<ITransformation>>(TransformationsParameterName, "", new ItemCollection<ITransformation>().AsReadOnly()));
+        Parameters.Add(new FixedValueParameter<ReadOnlyItemList<ITransformation>>(TransformationsParameterName, "", new ItemList<ITransformation>().AsReadOnly()));
         TransformationsParameter.Hidden = true;
       }
@@ -126,5 +126,5 @@
     }
 
-    protected DataAnalysisProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, IEnumerable<ITransformation> transformations) {
+    protected DataAnalysisProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, IList<ITransformation> transformations) {
       if (dataset == null) throw new ArgumentNullException("The dataset must not be null.");
       if (allowedInputVariables == null) throw new ArgumentNullException("The allowedInputVariables must not be null.");
@@ -144,5 +144,5 @@
       int testPartitionEnd = dataset.Rows;
 
-      var transformationsCollection = new ItemCollection<ITransformation>(transformations);
+      var transformationsList = new ItemList<ITransformation>(transformations);
 
       Parameters.Add(new FixedValueParameter<Dataset>(DatasetParameterName, "", dataset));
@@ -150,5 +150,5 @@
       Parameters.Add(new FixedValueParameter<IntRange>(TrainingPartitionParameterName, "", new IntRange(trainingPartitionStart, trainingPartitionEnd)));
       Parameters.Add(new FixedValueParameter<IntRange>(TestPartitionParameterName, "", new IntRange(testPartitionStart, testPartitionEnd)));
-      Parameters.Add(new FixedValueParameter<ReadOnlyItemCollection<ITransformation>>(TransformationsParameterName, "", transformationsCollection.AsReadOnly()));
+      Parameters.Add(new FixedValueParameter<ReadOnlyItemList<ITransformation>>(TransformationsParameterName, "", transformationsList.AsReadOnly()));
 
       TransformationsParameter.Hidden = true;
Index: /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Regression/RegressionProblemData.cs
===================================================================
--- /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Regression/RegressionProblemData.cs	(revision 10921)
+++ /branches/DataPreprocessing/HeuristicLab.Problems.DataAnalysis/3.4/Implementation/Regression/RegressionProblemData.cs	(revision 10922)
@@ -130,6 +130,6 @@
     }
 
-    public RegressionProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, string targetVariable, IEnumerable<ITransformation> transformations = null)
-      : base(dataset, allowedInputVariables, transformations ?? Enumerable.Empty<ITransformation>()) {
+    public RegressionProblemData(Dataset dataset, IEnumerable<string> allowedInputVariables, string targetVariable, IList<ITransformation> transformations = null)
+      : base(dataset, allowedInputVariables, transformations ?? new List<ITransformation>()) {
       var variables = InputVariables.Select(x => x.AsReadOnly()).ToList();
       Parameters.Add(new ConstrainedValueParameter<StringValue>(TargetVariableParameterName, new ItemSet<StringValue>(variables), variables.Where(x => x.Value == targetVariable).First()));
