Index: Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsPlugin.cs
===================================================================
diff -u -r2c7c991c5f2f2ef73d6683daad93d07ddb73ad6c -re402805257d7185512020535bd0df9cd01a7734e
--- Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsPlugin.cs	(.../GrassCoverErosionInwardsPlugin.cs)	(revision 2c7c991c5f2f2ef73d6683daad93d07ddb73ad6c)
+++ Ringtoets/GrassCoverErosionInwards/src/Ringtoets.GrassCoverErosionInwards.Plugin/GrassCoverErosionInwardsPlugin.cs	(.../GrassCoverErosionInwardsPlugin.cs)	(revision e402805257d7185512020535bd0df9cd01a7734e)
@@ -557,8 +557,13 @@
             bool isNestedGroup = parentData is GrassCoverErosionInwardsCalculationGroupContext;
 
             StrictContextMenuItem generateCalculationsItem = CreateGenerateCalculationsItem(context);
-            StrictContextMenuItem updateDikeProfileItem = CreateUpdateDikeProfileItem(context);
 
+            GrassCoverErosionInwardsCalculation[] calculations = context.WrappedData
+                                                                        .GetCalculations()
+                                                                        .OfType<GrassCoverErosionInwardsCalculation>()
+                                                                        .ToArray();
+            StrictContextMenuItem updateDikeProfileItem = CreateUpdateDikeProfileItem(calculations);
+
             builder.AddImportItem()
                    .AddExportItem()
                    .AddSeparator();
@@ -609,15 +614,16 @@
                           .Build();
         }
 
-        private StrictContextMenuItem CreateUpdateDikeProfileItem(GrassCoverErosionInwardsCalculationGroupContext nodeData)
+        private StrictContextMenuItem CreateUpdateDikeProfileItem(IEnumerable<GrassCoverErosionInwardsCalculation> calculations)
         {
             var contextMenuEnabled = true;
             string toolTipMessage = Resources.GrassCoverErosionInwardsPlugin_CreateUpdateDikeProfileItem_Update_all_calculations_with_DikeProfile_Tooltip;
-            IList<GrassCoverErosionInwardsCalculation> calculationsToUpdate = nodeData.WrappedData.GetCalculations()
-                                                                                      .OfType<GrassCoverErosionInwardsCalculation>()
-                                                                                      .Where(c => c.InputParameters.DikeProfile != null && !c.InputParameters.IsDikeProfileInputSynchronized)
-                                                                                      .ToList();
 
+            GrassCoverErosionInwardsCalculation[] calculationsToUpdate = calculations
+                .Where(calc => calc.InputParameters.DikeProfile != null
+                               && !calc.InputParameters.IsDikeProfileInputSynchronized)
+                .ToArray();
+
             if (!calculationsToUpdate.Any())
             {
                 contextMenuEnabled = false;