Index: Ringtoets/StabilityPointStructures/src/Ringtoets.StabilityPointStructures.Plugin/StabilityPointStructuresPlugin.cs
===================================================================
diff -u -rec82979ab7ef689a1687ebccc771d38f882c5bb7 -r2678ee310030f02f415f1799c61635081d754165
--- Ringtoets/StabilityPointStructures/src/Ringtoets.StabilityPointStructures.Plugin/StabilityPointStructuresPlugin.cs	(.../StabilityPointStructuresPlugin.cs)	(revision ec82979ab7ef689a1687ebccc771d38f882c5bb7)
+++ Ringtoets/StabilityPointStructures/src/Ringtoets.StabilityPointStructures.Plugin/StabilityPointStructuresPlugin.cs	(.../StabilityPointStructuresPlugin.cs)	(revision 2678ee310030f02f415f1799c61635081d754165)
@@ -504,6 +504,12 @@
             var parentGroupContext = (StabilityPointStructuresCalculationGroupContext) parentNodeData;
 
             parentGroupContext.WrappedData.Children.Remove(context.WrappedData);
+            foreach (var calculation in context.WrappedData.GetCalculations().Cast<StructuresCalculation<StabilityPointStructuresInput>>())
+            {
+                StructuresHelper.Delete(context.FailureMechanism.SectionResults,
+                                        calculation,
+                                        context.FailureMechanism.Calculations.Cast<StructuresCalculation<StabilityPointStructuresInput>>());
+            }
             parentGroupContext.NotifyObservers();
         }
 
@@ -582,6 +588,10 @@
             if (calculationGroupContext != null)
             {
                 calculationGroupContext.WrappedData.Children.Remove(context.WrappedData);
+                StructuresHelper.Delete(
+                    context.FailureMechanism.SectionResults, 
+                    context.WrappedData,
+                    context.FailureMechanism.Calculations.Cast<StructuresCalculation<StabilityPointStructuresInput>>());
                 calculationGroupContext.NotifyObservers();
             }
         }
Index: Ringtoets/StabilityPointStructures/test/Ringtoets.StabilityPointStructures.Forms.Test/TreeNodeInfos/StabilityPointStructuresCalculationContextTreeNodeInfoTest.cs
===================================================================
diff -u -ra14d1309ecf82ff5b0385a2f6e3b2c4a216a4184 -r2678ee310030f02f415f1799c61635081d754165
--- Ringtoets/StabilityPointStructures/test/Ringtoets.StabilityPointStructures.Forms.Test/TreeNodeInfos/StabilityPointStructuresCalculationContextTreeNodeInfoTest.cs	(.../StabilityPointStructuresCalculationContextTreeNodeInfoTest.cs)	(revision a14d1309ecf82ff5b0385a2f6e3b2c4a216a4184)
+++ Ringtoets/StabilityPointStructures/test/Ringtoets.StabilityPointStructures.Forms.Test/TreeNodeInfos/StabilityPointStructuresCalculationContextTreeNodeInfoTest.cs	(.../StabilityPointStructuresCalculationContextTreeNodeInfoTest.cs)	(revision 2678ee310030f02f415f1799c61635081d754165)
@@ -465,6 +465,40 @@
             CollectionAssert.DoesNotContain(group.Children, elementToBeRemoved);
         }
 
+        [Test]
+        public void OnNodeRemoved_CalculationInGroupAssignedToSection_CalculationDetachedFromSection()
+        {
+            // Setup
+            var group = new CalculationGroup();
+            var failureMechanism = new StabilityPointStructuresFailureMechanism();
+            var elementToBeRemoved = new StructuresCalculation<StabilityPointStructuresInput>();
+            var assessmentSectionStub = mocks.Stub<IAssessmentSection>();
+            var calculationContext = new StabilityPointStructuresCalculationContext(elementToBeRemoved,
+                                                                             failureMechanism,
+                                                                             assessmentSectionStub);
+            var groupContext = new StabilityPointStructuresCalculationGroupContext(group,
+                                                                            failureMechanism,
+                                                                            assessmentSectionStub);
+
+            mocks.ReplayAll();
+
+            group.Children.Add(elementToBeRemoved);
+
+            failureMechanism.AddSection(new FailureMechanismSection("section", new[]
+            {
+                new Point2D(0, 0)
+            }));
+
+            StabilityPointStructuresFailureMechanismSectionResult result = failureMechanism.SectionResults.First();
+            result.Calculation = elementToBeRemoved;
+
+            // Call
+            info.OnNodeRemoved(calculationContext, groupContext);
+
+            // Assert
+            Assert.IsNull(result.Calculation);
+        }
+
         public override void TearDown()
         {
             plugin.Dispose();
Index: Ringtoets/StabilityPointStructures/test/Ringtoets.StabilityPointStructures.Forms.Test/TreeNodeInfos/StabilityPointStructuresCalculationGroupContextTreeNodeInfoTest.cs
===================================================================
diff -u -rb78eb7cbd59f1bd31e72631b67b7e12b5b4477a5 -r2678ee310030f02f415f1799c61635081d754165
--- Ringtoets/StabilityPointStructures/test/Ringtoets.StabilityPointStructures.Forms.Test/TreeNodeInfos/StabilityPointStructuresCalculationGroupContextTreeNodeInfoTest.cs	(.../StabilityPointStructuresCalculationGroupContextTreeNodeInfoTest.cs)	(revision b78eb7cbd59f1bd31e72631b67b7e12b5b4477a5)
+++ Ringtoets/StabilityPointStructures/test/Ringtoets.StabilityPointStructures.Forms.Test/TreeNodeInfos/StabilityPointStructuresCalculationGroupContextTreeNodeInfoTest.cs	(.../StabilityPointStructuresCalculationGroupContextTreeNodeInfoTest.cs)	(revision 2678ee310030f02f415f1799c61635081d754165)
@@ -919,6 +919,78 @@
             CollectionAssert.DoesNotContain(parentGroup.Children, group);
         }
 
+        [Test]
+        public void OnNodeRemoved_CalculationInGroupAssignedToSection_CalculationDetachedFromSection()
+        {
+            // Setup
+            var failureMechanism = new StabilityPointStructuresFailureMechanism();
+            var assessmentSectionStub = mocks.Stub<IAssessmentSection>();
+            var group = new CalculationGroup();
+            var parentGroup = new CalculationGroup();
+            var nodeData = new StabilityPointStructuresCalculationGroupContext(group,
+                                                                       failureMechanism,
+                                                                       assessmentSectionStub);
+            var parentNodeData = new StabilityPointStructuresCalculationGroupContext(parentGroup,
+                                                                             failureMechanism,
+                                                                             assessmentSectionStub);
+
+            mocks.ReplayAll();
+
+            parentGroup.Children.Add(group);
+
+            failureMechanism.AddSection(new FailureMechanismSection("section", new[]
+            {
+                new Point2D(0, 0)
+            }));
+
+            var calculation = new StructuresCalculation<StabilityPointStructuresInput>();
+            group.Children.Add(calculation);
+
+            StabilityPointStructuresFailureMechanismSectionResult result = failureMechanism.SectionResults.First();
+            result.Calculation = calculation;
+
+            // Call
+            info.OnNodeRemoved(nodeData, parentNodeData);
+
+            // Assert
+            Assert.IsNull(result.Calculation);
+        }
+
+        [Test]
+        public void OnNodeRemoved_NestedCalculationGroupContainingCalculations_RemoveGroupAndCalculationsAndNotifyObservers()
+        {
+            // Setup
+            var observerMock = mocks.StrictMock<IObserver>();
+            var assessmentSectionStub = mocks.Stub<IAssessmentSection>();
+            var failureMechanism = new StabilityPointStructuresFailureMechanism();
+            var group = new CalculationGroup();
+            var parentGroup = new CalculationGroup();
+            var nodeData = new StabilityPointStructuresCalculationGroupContext(group,
+                                                                       failureMechanism,
+                                                                       assessmentSectionStub);
+            var parentNodeData = new StabilityPointStructuresCalculationGroupContext(parentGroup,
+                                                                             failureMechanism,
+                                                                             assessmentSectionStub);
+            var calculation = new StructuresCalculation<StabilityPointStructuresInput>();
+
+            observerMock.Expect(o => o.UpdateObserver());
+
+            mocks.ReplayAll();
+
+            group.Children.Add(calculation);
+            parentGroup.Children.Add(group);
+            parentNodeData.Attach(observerMock);
+
+            // Precondition
+            Assert.IsTrue(info.CanRemove(nodeData, parentNodeData));
+
+            // Call
+            info.OnNodeRemoved(nodeData, parentNodeData);
+
+            // Assert
+            CollectionAssert.DoesNotContain(parentGroup.Children, group);
+        }
+
         public override void TearDown()
         {
             plugin.Dispose();