Index: Riskeer/Common/src/Riskeer.Common.Data/UpdateDataStrategies/ReplaceDataStrategyBase.cs
===================================================================
diff -u -rd9119b8f4a74fb2a6f3ececeaea94f0e58513c52 -r16b38fdc1ec9ef4e2024feb5a1ff50f043e869b4
--- Riskeer/Common/src/Riskeer.Common.Data/UpdateDataStrategies/ReplaceDataStrategyBase.cs	(.../ReplaceDataStrategyBase.cs)	(revision d9119b8f4a74fb2a6f3ececeaea94f0e58513c52)
+++ Riskeer/Common/src/Riskeer.Common.Data/UpdateDataStrategies/ReplaceDataStrategyBase.cs	(.../ReplaceDataStrategyBase.cs)	(revision 16b38fdc1ec9ef4e2024feb5a1ff50f043e869b4)
@@ -35,7 +35,7 @@
     /// <typeparam name="TFailureMechanism">The type of the failure mechanism in which the target collection should be updated.</typeparam>
     public abstract class ReplaceDataStrategyBase<TTargetData, TFailureMechanism>
         where TTargetData : class
-        where TFailureMechanism : IFailureMechanism
+        where TFailureMechanism : class, IFailureMechanism
     {
         private readonly ObservableUniqueItemCollectionWithSourcePath<TTargetData> targetCollection;
 
Index: Riskeer/Common/src/Riskeer.Common.Data/UpdateDataStrategies/UpdateDataStrategyBase.cs
===================================================================
diff -u -rd9119b8f4a74fb2a6f3ececeaea94f0e58513c52 -r16b38fdc1ec9ef4e2024feb5a1ff50f043e869b4
--- Riskeer/Common/src/Riskeer.Common.Data/UpdateDataStrategies/UpdateDataStrategyBase.cs	(.../UpdateDataStrategyBase.cs)	(revision d9119b8f4a74fb2a6f3ececeaea94f0e58513c52)
+++ Riskeer/Common/src/Riskeer.Common.Data/UpdateDataStrategies/UpdateDataStrategyBase.cs	(.../UpdateDataStrategyBase.cs)	(revision 16b38fdc1ec9ef4e2024feb5a1ff50f043e869b4)
@@ -42,7 +42,7 @@
     /// <typeparam name="TFailureMechanism">The type of the failure mechanism in which the target collection should be updated.</typeparam>
     public abstract class UpdateDataStrategyBase<TTargetData, TFailureMechanism>
         where TTargetData : Observable
-        where TFailureMechanism : IFailureMechanism
+        where TFailureMechanism : class, IFailureMechanism
     {
         private readonly IEqualityComparer<TTargetData> equalityComparer;
         private readonly ObservableUniqueItemCollectionWithSourcePath<TTargetData> targetCollection;
Index: Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/ClearIllustrationPointsOfCalculationChangeHandlerBase.cs
===================================================================
diff -u -rd9119b8f4a74fb2a6f3ececeaea94f0e58513c52 -r16b38fdc1ec9ef4e2024feb5a1ff50f043e869b4
--- Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/ClearIllustrationPointsOfCalculationChangeHandlerBase.cs	(.../ClearIllustrationPointsOfCalculationChangeHandlerBase.cs)	(revision d9119b8f4a74fb2a6f3ececeaea94f0e58513c52)
+++ Riskeer/Common/src/Riskeer.Common.Forms/ChangeHandlers/ClearIllustrationPointsOfCalculationChangeHandlerBase.cs	(.../ClearIllustrationPointsOfCalculationChangeHandlerBase.cs)	(revision 16b38fdc1ec9ef4e2024feb5a1ff50f043e869b4)
@@ -31,7 +31,7 @@
     /// </summary>
     /// <typeparam name="TCalculation">The type of calculation.</typeparam>
     public abstract class ClearIllustrationPointsOfCalculationChangeHandlerBase<TCalculation> : IClearIllustrationPointsOfCalculationChangeHandler
-        where TCalculation : ICalculation
+        where TCalculation : class, ICalculation
     {
         private readonly IInquiryHelper inquiryHelper;
         protected TCalculation Calculation;