Index: Riskeer/Common/src/Riskeer.Common.Data/Calculation/CalculationGroupExtensions.cs
===================================================================
diff -u -r247659d91db1609d27f3d565203f62bd5b70abcc -r57eba4adfdfd8ae3cdfd27fa860b4544aa0eeafe
--- Riskeer/Common/src/Riskeer.Common.Data/Calculation/CalculationGroupExtensions.cs	(.../CalculationGroupExtensions.cs)	(revision 247659d91db1609d27f3d565203f62bd5b70abcc)
+++ Riskeer/Common/src/Riskeer.Common.Data/Calculation/CalculationGroupExtensions.cs	(.../CalculationGroupExtensions.cs)	(revision 57eba4adfdfd8ae3cdfd27fa860b4544aa0eeafe)
@@ -42,8 +42,7 @@
             {
                 children.Add(calculationItem);
 
-                var nestedCalculationGroup = calculationItem as CalculationGroup;
-                if (nestedCalculationGroup != null)
+                if (calculationItem is CalculationGroup nestedCalculationGroup)
                 {
                     children.AddRange(GetAllChildrenRecursive(nestedCalculationGroup));
                 }
@@ -63,14 +62,12 @@
             var calculations = new List<ICalculation>();
             foreach (ICalculationBase calculationItem in calculationGroup.Children)
             {
-                var calculation = calculationItem as ICalculation;
-                if (calculation != null)
+                if (calculationItem is ICalculation calculation)
                 {
                     calculations.Add(calculation);
                 }
 
-                var nestedCalculationGroup = calculationItem as CalculationGroup;
-                if (nestedCalculationGroup != null)
+                if (calculationItem is CalculationGroup nestedCalculationGroup)
                 {
                     calculations.AddRange(GetCalculations(nestedCalculationGroup));
                 }
@@ -80,20 +77,6 @@
         }
 
         /// <summary>
-        /// Clears the output of all calculations with output in a calculation group.
-        /// </summary>
-        /// <param name="calculationGroup">The calculation group to clear the output for.</param>
-        /// <remarks>The calculation group is enumerated recursively, also taking into account nested calculations.</remarks>
-        public static void ClearCalculationOutput(this CalculationGroup calculationGroup)
-        {
-            foreach (ICalculation calc in calculationGroup.GetCalculations().Where(c => c.HasOutput))
-            {
-                calc.ClearOutput();
-                calc.NotifyObservers();
-            }
-        }
-
-        /// <summary>
         /// Method for determining if one or more calculations in a calculation group have output.
         /// </summary>
         /// <param name="calculationGroup">The calculation group to check the output for.</param>
Index: Riskeer/Common/src/Riskeer.Common.Forms/TreeNodeInfos/RiskeerContextMenuItemFactory.cs
===================================================================
diff -u -rb7bf733eaf3766a4fe3808ceef56ce2843fc2daa -r57eba4adfdfd8ae3cdfd27fa860b4544aa0eeafe
--- Riskeer/Common/src/Riskeer.Common.Forms/TreeNodeInfos/RiskeerContextMenuItemFactory.cs	(.../RiskeerContextMenuItemFactory.cs)	(revision b7bf733eaf3766a4fe3808ceef56ce2843fc2daa)
+++ Riskeer/Common/src/Riskeer.Common.Forms/TreeNodeInfos/RiskeerContextMenuItemFactory.cs	(.../RiskeerContextMenuItemFactory.cs)	(revision 57eba4adfdfd8ae3cdfd27fa860b4544aa0eeafe)
@@ -665,16 +665,6 @@
             calculationGroup.NotifyObservers();
         }
 
-        private static void ClearAllCalculationOutputInGroup(CalculationGroup calculationGroup)
-        {
-            if (MessageBox.Show(Resources.CalculationGroup_ClearOutput_Are_you_sure_clear_all_output, BaseResources.Confirm, MessageBoxButtons.OKCancel) != DialogResult.OK)
-            {
-                return;
-            }
-
-            calculationGroup.ClearCalculationOutput();
-        }
-
         private static void ClearCalculationOutput(ICalculation calculation)
         {
             if (MessageBox.Show(Resources.Calculation_ContextMenuStrip_Are_you_sure_clear_output, BaseResources.Confirm, MessageBoxButtons.OKCancel) != DialogResult.OK)
Index: Riskeer/Common/test/Riskeer.Common.Data.Test/Calculation/CalculationGroupExtensionsTest.cs
===================================================================
diff -u -rc4311504aa83ba59c5a7e80c0e9bc26650986c05 -r57eba4adfdfd8ae3cdfd27fa860b4544aa0eeafe
--- Riskeer/Common/test/Riskeer.Common.Data.Test/Calculation/CalculationGroupExtensionsTest.cs	(.../CalculationGroupExtensionsTest.cs)	(revision c4311504aa83ba59c5a7e80c0e9bc26650986c05)
+++ Riskeer/Common/test/Riskeer.Common.Data.Test/Calculation/CalculationGroupExtensionsTest.cs	(.../CalculationGroupExtensionsTest.cs)	(revision 57eba4adfdfd8ae3cdfd27fa860b4544aa0eeafe)
@@ -59,7 +59,7 @@
         }
 
         [Test]
-        public void GetCalculations_FromCalculationGroupWithGroupsAndCalculations_ReturnAllCalculationsRecursiveslyInAnyOrder()
+        public void GetCalculations_FromCalculationGroupWithGroupsAndCalculations_ReturnAllCalculationsRecursivelyInAnyOrder()
         {
             // Setup
             var mocks = new MockRepository();
@@ -100,49 +100,6 @@
         }
 
         [Test]
-        public void ClearCalculationOutput_ForCalculationGroupWithGroupsAndCalculations_OutputOfRelevantCalculationsIsClearedAndObserversAreNotified()
-        {
-            // Setup
-            var mocks = new MockRepository();
-            var calculation1 = mocks.StrictMock<ICalculation>();
-            var calculation2 = mocks.StrictMock<ICalculation>();
-            var calculation3 = mocks.StrictMock<ICalculation>();
-            var calculation4 = mocks.StrictMock<ICalculation>();
-
-            calculation1.Expect(c => c.HasOutput).Return(true);
-            calculation2.Expect(c => c.HasOutput).Return(true);
-            calculation3.Expect(c => c.HasOutput).Return(false);
-            calculation4.Expect(c => c.HasOutput).Return(false);
-            calculation1.Expect(c => c.ClearOutput());
-            calculation2.Expect(c => c.ClearOutput());
-            calculation1.Expect(c => c.NotifyObservers());
-            calculation2.Expect(c => c.NotifyObservers());
-
-            mocks.ReplayAll();
-
-            var subsubGroup = new CalculationGroup();
-            subsubGroup.Children.Add(calculation4);
-
-            var subgroup1 = new CalculationGroup();
-            subgroup1.Children.Add(calculation2);
-            subgroup1.Children.Add(subsubGroup);
-
-            var subgroup2 = new CalculationGroup();
-            subgroup2.Children.Add(calculation3);
-
-            var rootGroup = new CalculationGroup();
-            rootGroup.Children.Add(subgroup1);
-            rootGroup.Children.Add(calculation1);
-            rootGroup.Children.Add(subgroup2);
-
-            // Call
-            rootGroup.ClearCalculationOutput();
-
-            // Assert
-            mocks.VerifyAll();
-        }
-
-        [Test]
         public void HasOutput_ForCalculationGroupWithGroupsAndCalculationsWithoutOutput_ReturnsFalse()
         {
             // Setup