Index: Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Plugin/ClosingStructuresPlugin.cs
===================================================================
diff -u -r183d1e7ed095ea4e8024068bc4ddfcf3ac6997d3 -rb1712af5a19e0e5fa7037e14f61d9d9496483bfa
--- Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Plugin/ClosingStructuresPlugin.cs	(.../ClosingStructuresPlugin.cs)	(revision 183d1e7ed095ea4e8024068bc4ddfcf3ac6997d3)
+++ Ringtoets/ClosingStructures/src/Ringtoets.ClosingStructures.Plugin/ClosingStructuresPlugin.cs	(.../ClosingStructuresPlugin.cs)	(revision b1712af5a19e0e5fa7037e14f61d9d9496483bfa)
@@ -524,11 +524,12 @@
             var parentGroupContext = (ClosingStructuresCalculationGroupContext) parentNodeData;
 
             parentGroupContext.WrappedData.Children.Remove(context.WrappedData);
+            var closingStructuresCalculations = context.FailureMechanism.Calculations.Cast<StructuresCalculation<ClosingStructuresInput>>().ToArray();
             foreach (var calculation in context.WrappedData.GetCalculations().Cast<StructuresCalculation<ClosingStructuresInput>>())
             {
                 StructuresHelper.Delete(context.FailureMechanism.SectionResults,
                                         calculation,
-                                        context.FailureMechanism.Calculations.Cast<StructuresCalculation<ClosingStructuresInput>>());
+                                        closingStructuresCalculations);
             }
 
             parentGroupContext.WrappedData.Children.Remove(context.WrappedData);
Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsPlugin.cs
===================================================================
diff -u -rf70611f9af51a6ffc8cb4d8d28d1ea806104937b -rb1712af5a19e0e5fa7037e14f61d9d9496483bfa
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsPlugin.cs	(.../GrassCoverErosionInwardsPlugin.cs)	(revision f70611f9af51a6ffc8cb4d8d28d1ea806104937b)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsPlugin.cs	(.../GrassCoverErosionInwardsPlugin.cs)	(revision b1712af5a19e0e5fa7037e14f61d9d9496483bfa)
@@ -528,11 +528,12 @@
             var parentGroupContext = (GrassCoverErosionInwardsCalculationGroupContext) parentNodeData;
 
             parentGroupContext.WrappedData.Children.Remove(context.WrappedData);
+            var grassCoverErosionInwardsCalculations = context.FailureMechanism.Calculations.Cast<GrassCoverErosionInwardsCalculation>().ToArray();
             foreach (var calculation in context.WrappedData.GetCalculations().Cast<GrassCoverErosionInwardsCalculation>())
             {
                 GrassCoverErosionInwardsHelper.Delete(context.FailureMechanism.SectionResults,
                                                       calculation,
-                                                      context.FailureMechanism.Calculations.Cast<GrassCoverErosionInwardsCalculation>());
+                                                      grassCoverErosionInwardsCalculations);
             }
             parentGroupContext.NotifyObservers();
         }
Index: Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Plugin/HeightStructuresPlugin.cs
===================================================================
diff -u -r60233a739e6b40a3182f53bb9ebd923703bd745c -rb1712af5a19e0e5fa7037e14f61d9d9496483bfa
--- Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Plugin/HeightStructuresPlugin.cs	(.../HeightStructuresPlugin.cs)	(revision 60233a739e6b40a3182f53bb9ebd923703bd745c)
+++ Ringtoets/HeightStructures/src/Ringtoets.HeightStructures.Plugin/HeightStructuresPlugin.cs	(.../HeightStructuresPlugin.cs)	(revision b1712af5a19e0e5fa7037e14f61d9d9496483bfa)
@@ -504,11 +504,12 @@
             var parentGroupContext = (HeightStructuresCalculationGroupContext) parentNodeData;
 
             parentGroupContext.WrappedData.Children.Remove(context.WrappedData);
+            var heightStructuresCalculations = context.FailureMechanism.Calculations.Cast<StructuresCalculation<HeightStructuresInput>>().ToArray();
             foreach (var calculation in context.WrappedData.GetCalculations().Cast<StructuresCalculation<HeightStructuresInput>>())
             {
                 StructuresHelper.Delete(context.FailureMechanism.SectionResults,
                                         calculation,
-                                        context.FailureMechanism.Calculations.Cast<StructuresCalculation<HeightStructuresInput>>());
+                                        heightStructuresCalculations);
             }
             parentGroupContext.NotifyObservers();
         }
Index: Ringtoets/StabilityPointStructures/src/Ringtoets.StabilityPointStructures.Plugin/StabilityPointStructuresPlugin.cs
===================================================================
diff -u -r2678ee310030f02f415f1799c61635081d754165 -rb1712af5a19e0e5fa7037e14f61d9d9496483bfa
--- Ringtoets/StabilityPointStructures/src/Ringtoets.StabilityPointStructures.Plugin/StabilityPointStructuresPlugin.cs	(.../StabilityPointStructuresPlugin.cs)	(revision 2678ee310030f02f415f1799c61635081d754165)
+++ Ringtoets/StabilityPointStructures/src/Ringtoets.StabilityPointStructures.Plugin/StabilityPointStructuresPlugin.cs	(.../StabilityPointStructuresPlugin.cs)	(revision b1712af5a19e0e5fa7037e14f61d9d9496483bfa)
@@ -453,8 +453,8 @@
             bool structuresAvailable = stabilityPointStructures.Any();
 
             string stabilityPointStructuresCalculationGroupContextToolTip = structuresAvailable
-                                                                         ? RingtoetsCommonFormsResources.StructuresPlugin_Generate_calculations_for_selected_structures
-                                                                         : RingtoetsCommonFormsResources.StructuresPlugin_No_structures_to_generate_for;
+                                                                                ? RingtoetsCommonFormsResources.StructuresPlugin_Generate_calculations_for_selected_structures
+                                                                                : RingtoetsCommonFormsResources.StructuresPlugin_No_structures_to_generate_for;
 
             return new StrictContextMenuItem(RingtoetsCommonFormsResources.CalculationsGroup_Generate_calculations,
                                              stabilityPointStructuresCalculationGroupContextToolTip,
@@ -504,11 +504,12 @@
             var parentGroupContext = (StabilityPointStructuresCalculationGroupContext) parentNodeData;
 
             parentGroupContext.WrappedData.Children.Remove(context.WrappedData);
+            var stabilityPointStructuresCalculations = context.FailureMechanism.Calculations.Cast<StructuresCalculation<StabilityPointStructuresInput>>().ToArray();
             foreach (var calculation in context.WrappedData.GetCalculations().Cast<StructuresCalculation<StabilityPointStructuresInput>>())
             {
                 StructuresHelper.Delete(context.FailureMechanism.SectionResults,
                                         calculation,
-                                        context.FailureMechanism.Calculations.Cast<StructuresCalculation<StabilityPointStructuresInput>>());
+                                        stabilityPointStructuresCalculations);
             }
             parentGroupContext.NotifyObservers();
         }
@@ -589,7 +590,7 @@
             {
                 calculationGroupContext.WrappedData.Children.Remove(context.WrappedData);
                 StructuresHelper.Delete(
-                    context.FailureMechanism.SectionResults, 
+                    context.FailureMechanism.SectionResults,
                     context.WrappedData,
                     context.FailureMechanism.Calculations.Cast<StructuresCalculation<StabilityPointStructuresInput>>());
                 calculationGroupContext.NotifyObservers();