Index: Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/GrassCoverErosionOutwardsFailureMechanismPropertyChangeHandler.cs
===================================================================
diff -u -re2f91813f3aae8eb2daef6ff1ffac61d197148a8 -re853e0f8c9bfa09ee56ce3e323d82b1d42446e02
--- Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/GrassCoverErosionOutwardsFailureMechanismPropertyChangeHandler.cs	(.../GrassCoverErosionOutwardsFailureMechanismPropertyChangeHandler.cs)	(revision e2f91813f3aae8eb2daef6ff1ffac61d197148a8)
+++ Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/GrassCoverErosionOutwardsFailureMechanismPropertyChangeHandler.cs	(.../GrassCoverErosionOutwardsFailureMechanismPropertyChangeHandler.cs)	(revision e853e0f8c9bfa09ee56ce3e323d82b1d42446e02)
@@ -31,14 +31,16 @@
 
         protected override IEnumerable<IObservable> PropertyChanged(GrassCoverErosionOutwardsFailureMechanism failureMechanism)
         {
-            if (failureMechanism == null)
-            {
-                throw new ArgumentNullException(nameof(failureMechanism));
-            }
+            var affectedObjects = new List<IObservable>(base.PropertyChanged(failureMechanism));
 
-            var affectedObjects = RingtoetsCommonDataSynchronizationService.ClearHydraulicBoundaryLocationOutput(
+            IEnumerable<IObservable> affectedLocations = RingtoetsCommonDataSynchronizationService.ClearHydraulicBoundaryLocationOutput(
                 failureMechanism.HydraulicBoundaryLocations);
-            return affectedObjects.Concat(base.PropertyChanged(failureMechanism));
+
+            if (affectedLocations.Any())
+            {
+                affectedObjects.Add(failureMechanism.HydraulicBoundaryLocations);
+            }
+            return affectedObjects;
         }
     }
 }
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