Index: Riskeer/Piping/src/Riskeer.Piping.Plugin/PipingPlugin.cs
===================================================================
diff -u -rb03e4918d94a87bef23992b2d0b242cc6b8719c6 -r28fbc1322470012f3546c1d7343dfb73ae0cefd1
--- Riskeer/Piping/src/Riskeer.Piping.Plugin/PipingPlugin.cs	(.../PipingPlugin.cs)	(revision b03e4918d94a87bef23992b2d0b242cc6b8719c6)
+++ Riskeer/Piping/src/Riskeer.Piping.Plugin/PipingPlugin.cs	(.../PipingPlugin.cs)	(revision 28fbc1322470012f3546c1d7343dfb73ae0cefd1)
@@ -680,31 +680,36 @@
 
             foreach (ICalculationBase item in nodeData.WrappedData.Children)
             {
-                var calculation = item as PipingCalculationScenario;
-                var group = item as CalculationGroup;
-
-                if (calculation != null)
+                switch (item)
                 {
-                    childNodeObjects.Add(new PipingCalculationScenarioContext(calculation,
-                                                                              nodeData.WrappedData,
-                                                                              nodeData.AvailablePipingSurfaceLines,
-                                                                              nodeData.AvailableStochasticSoilModels,
-                                                                              nodeData.FailureMechanism,
-                                                                              nodeData.AssessmentSection));
+                    case PipingCalculationScenario semiProbabilisticCalculation:
+                        childNodeObjects.Add(new PipingCalculationScenarioContext(semiProbabilisticCalculation,
+                                                                                  nodeData.WrappedData,
+                                                                                  nodeData.AvailablePipingSurfaceLines,
+                                                                                  nodeData.AvailableStochasticSoilModels,
+                                                                                  nodeData.FailureMechanism,
+                                                                                  nodeData.AssessmentSection));
+                        break;
+                    case ProbabilisticPipingCalculation probabilisticCalculation:
+                        childNodeObjects.Add(new ProbabilisticPipingCalculationContext(probabilisticCalculation,
+                                                                                       nodeData.WrappedData,
+                                                                                       nodeData.AvailablePipingSurfaceLines,
+                                                                                       nodeData.AvailableStochasticSoilModels,
+                                                                                       nodeData.FailureMechanism,
+                                                                                       nodeData.AssessmentSection));
+                        break;
+                    case CalculationGroup group:
+                        childNodeObjects.Add(new PipingCalculationGroupContext(group,
+                                                                               nodeData.WrappedData,
+                                                                               nodeData.AvailablePipingSurfaceLines,
+                                                                               nodeData.AvailableStochasticSoilModels,
+                                                                               nodeData.FailureMechanism,
+                                                                               nodeData.AssessmentSection));
+                        break;
+                    default:
+                        childNodeObjects.Add(item);
+                        break;
                 }
-                else if (group != null)
-                {
-                    childNodeObjects.Add(new PipingCalculationGroupContext(group,
-                                                                           nodeData.WrappedData,
-                                                                           nodeData.AvailablePipingSurfaceLines,
-                                                                           nodeData.AvailableStochasticSoilModels,
-                                                                           nodeData.FailureMechanism,
-                                                                           nodeData.AssessmentSection));
-                }
-                else
-                {
-                    childNodeObjects.Add(item);
-                }
             }
 
             return childNodeObjects.ToArray();
Index: Riskeer/Piping/test/Riskeer.Piping.Plugin.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs
===================================================================
diff -u -rb03e4918d94a87bef23992b2d0b242cc6b8719c6 -r28fbc1322470012f3546c1d7343dfb73ae0cefd1
--- Riskeer/Piping/test/Riskeer.Piping.Plugin.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs	(.../PipingCalculationGroupContextTreeNodeInfoTest.cs)	(revision b03e4918d94a87bef23992b2d0b242cc6b8719c6)
+++ Riskeer/Piping/test/Riskeer.Piping.Plugin.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs	(.../PipingCalculationGroupContextTreeNodeInfoTest.cs)	(revision 28fbc1322470012f3546c1d7343dfb73ae0cefd1)
@@ -147,13 +147,15 @@
             // Setup
             var calculationItem = mocks.StrictMock<ICalculationBase>();
 
-            var childCalculation = new PipingCalculationScenario(new GeneralPipingInput());
+            var semiProbabilisticChildCalculation = new PipingCalculationScenario(new GeneralPipingInput());
+            var probabilisticChildCalculation = new ProbabilisticPipingCalculation(new GeneralPipingInput());
 
             var childGroup = new CalculationGroup();
 
             var group = new CalculationGroup();
             group.Children.Add(calculationItem);
-            group.Children.Add(childCalculation);
+            group.Children.Add(semiProbabilisticChildCalculation);
+            group.Children.Add(probabilisticChildCalculation);
             group.Children.Add(childGroup);
 
             var pipingFailureMechanism = new PipingFailureMechanism();
@@ -174,11 +176,18 @@
             // Assert
             Assert.AreEqual(group.Children.Count, children.Length);
             Assert.AreSame(calculationItem, children[0]);
-            var returnedCalculationContext = (PipingCalculationScenarioContext) children[1];
-            Assert.AreSame(childCalculation, returnedCalculationContext.WrappedData);
-            Assert.AreSame(group, returnedCalculationContext.Parent);
-            Assert.AreSame(pipingFailureMechanism, returnedCalculationContext.FailureMechanism);
-            var returnedCalculationGroupContext = (PipingCalculationGroupContext) children[2];
+            
+            var returnedSemiProbabilisticCalculationContext = (PipingCalculationScenarioContext) children[1];
+            Assert.AreSame(semiProbabilisticChildCalculation, returnedSemiProbabilisticCalculationContext.WrappedData);
+            Assert.AreSame(group, returnedSemiProbabilisticCalculationContext.Parent);
+            Assert.AreSame(pipingFailureMechanism, returnedSemiProbabilisticCalculationContext.FailureMechanism);
+            
+            var returnedProbabilisticCalculationContext = (ProbabilisticPipingCalculationContext) children[2];
+            Assert.AreSame(probabilisticChildCalculation, returnedProbabilisticCalculationContext.WrappedData);
+            Assert.AreSame(group, returnedProbabilisticCalculationContext.Parent);
+            Assert.AreSame(pipingFailureMechanism, returnedProbabilisticCalculationContext.FailureMechanism);
+            
+            var returnedCalculationGroupContext = (PipingCalculationGroupContext) children[3];
             Assert.AreSame(childGroup, returnedCalculationGroupContext.WrappedData);
             Assert.AreSame(group, returnedCalculationGroupContext.Parent);
             Assert.AreSame(pipingFailureMechanism, returnedCalculationGroupContext.FailureMechanism);