Index: Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/Views/GrassCoverErosionOutwardsWaveHeightLocationsView.cs
===================================================================
diff -u -rf5bac1f11df4ee4881109371c50120763e303642 -r1b9d535d0b4f21bd0adb64184e5273d8bf691c4e
--- Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/Views/GrassCoverErosionOutwardsWaveHeightLocationsView.cs	(.../GrassCoverErosionOutwardsWaveHeightLocationsView.cs)	(revision f5bac1f11df4ee4881109371c50120763e303642)
+++ Ringtoets/GrassCoverErosionOutwards/src/Ringtoets.GrassCoverErosionOutwards.Forms/Views/GrassCoverErosionOutwardsWaveHeightLocationsView.cs	(.../GrassCoverErosionOutwardsWaveHeightLocationsView.cs)	(revision 1b9d535d0b4f21bd0adb64184e5273d8bf691c4e)
@@ -29,6 +29,7 @@
 using Ringtoets.GrassCoverErosionOutwards.Forms.PresentationObjects;
 using Ringtoets.GrassCoverErosionOutwards.Forms.Properties;
 using Ringtoets.GrassCoverErosionOutwards.Service.MessageProviders;
+using RingtoetsCommonFormsResources = Ringtoets.Common.Forms.Properties.Resources;
 
 namespace Ringtoets.GrassCoverErosionOutwards.Forms.Views
 {
@@ -37,14 +38,19 @@
     /// for the <see cref="GrassCoverErosionOutwardsFailureMechanism"/></summary>
     public class GrassCoverErosionOutwardsWaveHeightLocationsView : HydraulicBoundaryLocationsView<WaveHeightLocationRow>
     {
-        private readonly Observer hydraulicBoundaryLocationObserver;
+        private readonly Observer assessmentSectionObserver;
+        private readonly Observer hydraulicBoundaryLocationsObserver;
 
+        private IAssessmentSection assessmentSection;
+        private GrassCoverErosionOutwardsFailureMechanism failureMechanism;
+
         /// <summary>
         /// Creates a new instance of <see cref="GrassCoverErosionOutwardsWaveHeightLocationsView"/>
         /// </summary>
         public GrassCoverErosionOutwardsWaveHeightLocationsView()
         {
-            hydraulicBoundaryLocationObserver = new Observer(UpdateHydraulicBoundaryLocations);
+            assessmentSectionObserver = new Observer(UpdateCalculateForSelectedButton);
+            hydraulicBoundaryLocationsObserver = new Observer(UpdateHydraulicBoundaryLocations);
         }
 
         public override object Data
@@ -57,17 +63,39 @@
             {
                 var data = (ObservableList<HydraulicBoundaryLocation>) value;
                 base.Data = data;
-                hydraulicBoundaryLocationObserver.Observable = data;
+                hydraulicBoundaryLocationsObserver.Observable = data;
             }
         }
 
-        public override IAssessmentSection AssessmentSection { get; set; }
+        public override IAssessmentSection AssessmentSection
+        {
+            get
+            {
+                return assessmentSection;
+            }
+            set
+            {
+                assessmentSection = value;
+                assessmentSectionObserver.Observable = assessmentSection;
+            }
+        }
 
         /// <summary>
         /// Gets or sets the <see cref="GrassCoverErosionOutwardsFailureMechanism"/> for which the
         /// hydraulic boundary locations are shown.
         /// </summary>
-        public GrassCoverErosionOutwardsFailureMechanism FailureMechanism { get; set; }
+        public GrassCoverErosionOutwardsFailureMechanism FailureMechanism
+        {
+            get
+            {
+                return failureMechanism;
+            }
+            set
+            {
+                failureMechanism = value;
+                UpdateCalculateForSelectedButton();
+            }
+        }
 
         protected override WaveHeightLocationRow CreateNewRow(HydraulicBoundaryLocation location)
         {
@@ -114,10 +142,21 @@
 
         protected override void Dispose(bool disposing)
         {
-            hydraulicBoundaryLocationObserver.Dispose();
+            assessmentSectionObserver.Dispose();
+            hydraulicBoundaryLocationsObserver.Dispose();
             base.Dispose(disposing);
         }
 
+        protected override string ValidateCalculatableObjects()
+        {
+            if (FailureMechanism != null && FailureMechanism.Contribution <= 0)
+            {
+                return RingtoetsCommonFormsResources.Contribution_of_failure_mechanism_zero;
+            }
+
+            return base.ValidateCalculatableObjects();
+        }
+
         private void UpdateHydraulicBoundaryLocations()
         {
             if (IsDataGridDataSourceChanged())
Index: Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Forms.Test/Views/GrassCoverErosionOutwardsWaveHeightLocationsViewTest.cs
===================================================================
diff -u -rf5bac1f11df4ee4881109371c50120763e303642 -r1b9d535d0b4f21bd0adb64184e5273d8bf691c4e
--- Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Forms.Test/Views/GrassCoverErosionOutwardsWaveHeightLocationsViewTest.cs	(.../GrassCoverErosionOutwardsWaveHeightLocationsViewTest.cs)	(revision f5bac1f11df4ee4881109371c50120763e303642)
+++ Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Forms.Test/Views/GrassCoverErosionOutwardsWaveHeightLocationsViewTest.cs	(.../GrassCoverErosionOutwardsWaveHeightLocationsViewTest.cs)	(revision 1b9d535d0b4f21bd0adb64184e5273d8bf691c4e)
@@ -52,18 +52,22 @@
         private const int locationIdColumnIndex = 2;
         private const int locationColumnIndex = 3;
         private const int locationWaveHeightColumnIndex = 4;
+
         private Form testForm;
+        private MockRepository mockRepository;
 
         [SetUp]
         public void Setup()
         {
             testForm = new Form();
+            mockRepository = new MockRepository();
         }
 
         [TearDown]
         public void TearDown()
         {
             testForm.Dispose();
+            mockRepository.VerifyAll();
         }
 
         [Test]
@@ -279,7 +283,6 @@
             var rows = dataGridView.Rows;
             rows[0].Cells[locationCalculateColumnIndex].Value = true;
 
-            var mockRepository = new MockRepository();
             var guiServiceMock = mockRepository.StrictMock<IHydraulicBoundaryLocationCalculationGuiService>();
 
             var observer = mockRepository.StrictMock<IObserver>();
@@ -304,7 +307,8 @@
             assessmentSectionStub.Stub(ass => ass.Id).Return(string.Empty);
             assessmentSectionStub.Stub(ass => ass.FailureMechanismContribution)
                                  .Return(new FailureMechanismContribution(Enumerable.Empty<IFailureMechanism>(), 1, 1));
-
+            assessmentSectionStub.Stub(a => a.Attach(null)).IgnoreArguments();
+            assessmentSectionStub.Stub(a => a.Detach(null)).IgnoreArguments();
             mockRepository.ReplayAll();
 
             view.AssessmentSection = assessmentSectionStub;
@@ -327,7 +331,6 @@
             Assert.IsTrue((bool) rows[0].Cells[locationCalculateColumnIndex].Value);
             Assert.IsFalse((bool) rows[1].Cells[locationCalculateColumnIndex].Value);
             Assert.IsFalse((bool) rows[2].Cells[locationCalculateColumnIndex].Value);
-            mockRepository.VerifyAll();
         }
 
         [Test]
Index: Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Plugin.Test/ViewInfos/GrassCoverErosionOutwardsWaveHeightLocationsViewInfoTest.cs
===================================================================
diff -u -re182f6f394aa75e739467a77e7bcacd9a8b25429 -r1b9d535d0b4f21bd0adb64184e5273d8bf691c4e
--- Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Plugin.Test/ViewInfos/GrassCoverErosionOutwardsWaveHeightLocationsViewInfoTest.cs	(.../GrassCoverErosionOutwardsWaveHeightLocationsViewInfoTest.cs)	(revision e182f6f394aa75e739467a77e7bcacd9a8b25429)
+++ Ringtoets/GrassCoverErosionOutwards/test/Ringtoets.GrassCoverErosionOutwards.Plugin.Test/ViewInfos/GrassCoverErosionOutwardsWaveHeightLocationsViewInfoTest.cs	(.../GrassCoverErosionOutwardsWaveHeightLocationsViewInfoTest.cs)	(revision 1b9d535d0b4f21bd0adb64184e5273d8bf691c4e)
@@ -132,6 +132,8 @@
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
             });
+            assessmentSection.Stub(a => a.Attach(null)).IgnoreArguments();
+            assessmentSection.Stub(a => a.Detach(null)).IgnoreArguments();
             mocks.ReplayAll();
 
             using (var view = new GrassCoverErosionOutwardsWaveHeightLocationsView())
@@ -156,12 +158,12 @@
             var mocks = new MockRepository();
             var assessmentSectionA = mocks.Stub<IAssessmentSection>();
             var assessmentSectionB = mocks.Stub<IAssessmentSection>();
-
             assessmentSectionA.Stub(a => a.GetFailureMechanisms()).Return(new[]
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
             });
-
+            assessmentSectionA.Stub(a => a.Attach(null)).IgnoreArguments();
+            assessmentSectionA.Stub(a => a.Detach(null)).IgnoreArguments();
             assessmentSectionB.Stub(a => a.GetFailureMechanisms()).Return(new[]
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
@@ -193,6 +195,8 @@
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
             });
+            assessmentSection.Stub(a => a.Attach(null)).IgnoreArguments();
+            assessmentSection.Stub(a => a.Detach(null)).IgnoreArguments();
             mocks.ReplayAll();
 
             var grassCoverErosionOutwardsFailureMechanismContext = new GrassCoverErosionOutwardsFailureMechanismContext(
@@ -221,11 +225,12 @@
             var mocks = new MockRepository();
             var assessmentSectionA = mocks.Stub<IAssessmentSection>();
             var assessmentSectionB = mocks.Stub<IAssessmentSection>();
-
             assessmentSectionA.Stub(a => a.GetFailureMechanisms()).Return(new[]
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
             });
+            assessmentSectionA.Stub(a => a.Attach(null)).IgnoreArguments();
+            assessmentSectionA.Stub(a => a.Detach(null)).IgnoreArguments();
             assessmentSectionB.Stub(a => a.GetFailureMechanisms()).Return(new[]
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
@@ -256,18 +261,20 @@
         {
             // Setup
             var mocks = new MockRepository();
-            var assessmentSectionA = mocks.Stub<IAssessmentSection>();
-            assessmentSectionA.Stub(a => a.GetFailureMechanisms()).Return(new[]
+            var assessmentSection = mocks.Stub<IAssessmentSection>();
+            assessmentSection.Stub(a => a.GetFailureMechanisms()).Return(new[]
             {
                 new GrassCoverErosionOutwardsFailureMechanism()
             });
+            assessmentSection.Stub(a => a.Attach(null)).IgnoreArguments();
+            assessmentSection.Stub(a => a.Detach(null)).IgnoreArguments();
             mocks.ReplayAll();
 
             using (var view = new GrassCoverErosionOutwardsWaveHeightLocationsView())
             using (var plugin = new GrassCoverErosionOutwardsPlugin())
             {
                 var info = GetInfo(plugin);
-                view.AssessmentSection = assessmentSectionA;
+                view.AssessmentSection = assessmentSection;
 
                 // Call
                 var closeForData = info.CloseForData(view, new object());
@@ -295,7 +302,7 @@
             }
         }
 
-        private ViewInfo GetInfo(PluginBase plugin)
+        private static ViewInfo GetInfo(PluginBase plugin)
         {
             return plugin.GetViewInfos().FirstOrDefault(vi => vi.ViewType == typeof(GrassCoverErosionOutwardsWaveHeightLocationsView));
         }