Index: Ringtoets/Piping/src/Ringtoets.Piping.Plugin/PipingGuiPlugin.cs
===================================================================
diff -u -r1a390cf262c06e082830182276b6cb5da0aaef80 -rfd18531c4e5f5c1effb5d8dc2797c5cd57dd2aed
--- Ringtoets/Piping/src/Ringtoets.Piping.Plugin/PipingGuiPlugin.cs	(.../PipingGuiPlugin.cs)	(revision 1a390cf262c06e082830182276b6cb5da0aaef80)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Plugin/PipingGuiPlugin.cs	(.../PipingGuiPlugin.cs)	(revision fd18531c4e5f5c1effb5d8dc2797c5cd57dd2aed)
@@ -209,14 +209,14 @@
                 PipingFormsResources.PipingCalculationGroup_Add_PipingCalculationGroup,
                 PipingFormsResources.PipingFailureMechanism_Add_PipingCalculationGroup_Tooltip,
                 PipingFormsResources.AddFolderIcon,
-                (o, args) => AddCalculationGroup(failureMechanism, node)
+                (o, args) => AddCalculationGroup(failureMechanism, node, treeViewControl)
                 );
 
             var addCalculationItem = new StrictContextMenuItem(
                 PipingFormsResources.PipingCalculationGroup_Add_PipingCalculation,
                 PipingFormsResources.PipingFailureMechanism_Add_PipingCalculation_Tooltip,
                 PipingFormsResources.PipingIcon,
-                (s, e) => AddCalculation(failureMechanism, node)
+                (s, e) => AddCalculation(failureMechanism, node, treeViewControl)
                 );
 
             var validateAllItem = CreateValidateAllItem(failureMechanism);
@@ -314,7 +314,7 @@
             ActivityProgressDialogRunner.Run(Gui.MainWindow, GetAllPipingCalculationsResursively(failureMechanism).Select(calc => new PipingCalculationActivity(calc)));
         }
 
-        private void AddCalculationGroup(PipingFailureMechanism failureMechanism, TreeNode failureMechanismNode)
+        private void AddCalculationGroup(PipingFailureMechanism failureMechanism, TreeNode failureMechanismNode, TreeViewControl treeViewControl)
         {
             var calculation = new PipingCalculationGroup
             {
@@ -323,10 +323,10 @@
             failureMechanism.CalculationsGroup.Children.Add(calculation);
             failureMechanism.CalculationsGroup.NotifyObservers();
 
-            SelectNewlyAddedPipingFailureMechanismItemInTreeView(failureMechanismNode);
+            SelectNewlyAddedPipingFailureMechanismItemInTreeView(failureMechanismNode, treeViewControl);
         }
 
-        private void AddCalculation(PipingFailureMechanism failureMechanism, TreeNode failureMechanismNode)
+        private void AddCalculation(PipingFailureMechanism failureMechanism, TreeNode failureMechanismNode, TreeViewControl treeViewControl)
         {
             var calculation = new PipingCalculation
             {
@@ -335,10 +335,10 @@
             failureMechanism.CalculationsGroup.Children.Add(calculation);
             failureMechanism.CalculationsGroup.NotifyObservers();
 
-            SelectNewlyAddedPipingFailureMechanismItemInTreeView(failureMechanismNode);
+            SelectNewlyAddedPipingFailureMechanismItemInTreeView(failureMechanismNode, treeViewControl);
         }
 
-        private void SelectNewlyAddedPipingFailureMechanismItemInTreeView(TreeNode failureMechanismNode)
+        private void SelectNewlyAddedPipingFailureMechanismItemInTreeView(TreeNode failureMechanismNode, TreeViewControl treeViewControl)
         {
             if (!failureMechanismNode.IsExpanded)
             {
@@ -355,7 +355,7 @@
                 failureMechanismsCalculationsNode.Expand();
             }
 
-            failureMechanismNode.TreeView.SelectedNode = newlyAddedGroupNode;
+            treeViewControl.SelectNodeForData(newlyAddedGroupNode.Tag);
         }
 
         private static IEnumerable<PipingCalculation> GetAllPipingCalculationsResursively(PipingFailureMechanism failureMechanism)
@@ -552,7 +552,7 @@
                     group.Children.Add(newGroup);
                     nodeData.NotifyObservers();
 
-                    SelectNewlyAddedPipingCalculationGroupContextItemInTreeView(node);
+                    SelectNewlyAddedPipingCalculationGroupContextItemInTreeView(node, treeViewControl);
                 });
 
             var addCalculationItem = new StrictContextMenuItem(
@@ -568,7 +568,7 @@
                     group.Children.Add(calculation);
                     nodeData.NotifyObservers();
 
-                    SelectNewlyAddedPipingCalculationGroupContextItemInTreeView(node);
+                    SelectNewlyAddedPipingCalculationGroupContextItemInTreeView(node, treeViewControl);
                 });
 
             var validateAllItem = CreateValidateAllItem(group);
@@ -806,15 +806,15 @@
             return new DroppingPipingCalculationToNewContainer(originalOwnerContext, target);
         }
 
-        private void SelectNewlyAddedPipingCalculationGroupContextItemInTreeView(TreeNode node)
+        private void SelectNewlyAddedPipingCalculationGroupContextItemInTreeView(TreeNode node, TreeViewControl treeViewControl)
         {
             // Expand parent of 'newItem' to ensure its selected state is visible.
             if (!node.IsExpanded)
             {
                 node.Expand();
             }
             TreeNode newlyAppendedNodeForNewItem = node.Nodes.OfType<TreeNode>().Last();
-            node.TreeView.SelectedNode = newlyAppendedNodeForNewItem;
+            treeViewControl.SelectNodeForData(newlyAppendedNodeForNewItem.Tag);
         }
 
         #region Nested Types: DroppingPipingCalculationInContainerStrategy and implementations
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs
===================================================================
diff -u -r63c199ecc57c7d9344fce238426ed51bbf352552 -rfd18531c4e5f5c1effb5d8dc2797c5cd57dd2aed
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs	(.../PipingCalculationGroupContextTreeNodeInfoTest.cs)	(revision 63c199ecc57c7d9344fce238426ed51bbf352552)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/TreeNodeInfos/PipingCalculationGroupContextTreeNodeInfoTest.cs	(.../PipingCalculationGroupContextTreeNodeInfoTest.cs)	(revision fd18531c4e5f5c1effb5d8dc2797c5cd57dd2aed)
@@ -1089,8 +1089,8 @@
         public void GetContextMenu_ClickOnAddGroupItem_AddGroupToCalculationGroupAndNotifyObservers()
         {
             // Setup
+            var tag = new object();
             var gui = mocks.StrictMock<IGui>();
-            var treeViewControl = mocks.StrictMock<TreeViewControl>();
             var menuBuilder = new CustomItemsOnlyContextMenuBuilder();
             var group = new PipingCalculationGroup();
             var nodeData = new PipingCalculationGroupContext(group,
@@ -1103,10 +1103,12 @@
             var observer = mocks.StrictMock<IObserver>();
             observer.Expect(o => o.UpdateObserver());
 
-            var newCalculationGroupContextNode = new TreeNode();
+            var treeViewControl = mocks.StrictMock<TreeViewControl>();
+            treeViewControl.Expect(tvc => tvc.SelectNodeForData(tag));
 
+            var newCalculationGroupContextNode = new TreeNode { Tag = tag };
+
             // Parent node of newly added item, should be expanded from collapsed state to show selected node:
-            var treeView = new TreeView();
             var parentNode = new TreeNode();
             var node = new TreeNode
             {
@@ -1117,8 +1119,6 @@
 
             parentNode.Nodes.Add(node);
 
-            treeView.Nodes.Add(parentNode);
-
             gui.Expect(cmp => cmp.Get(node, info, treeViewControl)).Return(menuBuilder);
 
             mocks.ReplayAll();
@@ -1144,18 +1144,15 @@
             Assert.AreEqual("Nieuwe map (1)", newlyAddedItem.Name,
                             "An item with the same name default name already exists, therefore '(1)' needs to be appended.");
 
-            Assert.AreSame(newCalculationGroupContextNode, treeView.SelectedNode,
-                           "The node of the newly added item should be selected.");
-
             mocks.VerifyAll();
         }
 
         [Test]
         public void GetContextMenu_ClickOnAddCalculationItem_AddCalculationToCalculationGroupAndNotifyObservers()
         {
             // Setup
+            var tag = new object();
             var gui = mocks.StrictMock<IGui>();
-            var treeViewControl = mocks.StrictMock<TreeViewControl>();
             var menuBuilder = new CustomItemsOnlyContextMenuBuilder();
             var group = new PipingCalculationGroup();
             var nodeData = new PipingCalculationGroupContext(group,
@@ -1168,10 +1165,12 @@
             var observer = mocks.StrictMock<IObserver>();
             observer.Expect(o => o.UpdateObserver());
 
-            var newCalculationContextNode = new TreeNode();
+            var treeViewControl = mocks.StrictMock<TreeViewControl>();
+            treeViewControl.Expect(tvc => tvc.SelectNodeForData(tag));
 
+            var newCalculationContextNode = new TreeNode { Tag = tag };
+
             // Parent node of newly added item, should be expanded from collapsed state to show selected node:
-            var treeView = new TreeView();
             var parentNode = new TreeNode();
             var node = new TreeNode
             {
@@ -1182,8 +1181,6 @@
 
             parentNode.Nodes.Add(node);
 
-            treeView.Nodes.Add(parentNode);
-
             gui.Expect(cmp => cmp.Get(node, info, treeViewControl)).Return(menuBuilder);
 
             mocks.ReplayAll();
@@ -1209,9 +1206,6 @@
             Assert.AreEqual("Nieuwe berekening (1)", newlyAddedItem.Name,
                             "An item with the same name default name already exists, therefore '(1)' needs to be appended.");
 
-            Assert.AreSame(newCalculationContextNode, node.TreeView.SelectedNode,
-                           "The node of the newly added item should be selected.");
-
             mocks.VerifyAll();
         }