Index: Core/Common/src/Core.Common.Gui/GuiCommandHandler.cs
===================================================================
diff -u -r2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Core/Common/src/Core.Common.Gui/GuiCommandHandler.cs	(.../GuiCommandHandler.cs)	(revision 2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2)
+++ Core/Common/src/Core.Common.Gui/GuiCommandHandler.cs	(.../GuiCommandHandler.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -135,17 +135,17 @@
 
         public bool CanImportOn(object obj)
         {
-            return gui.ApplicationCore.GetSupportedFileImporters(gui.Selection).Any();
+            return gui.ApplicationCore.GetSupportedFileImporters(obj).Any();
         }
 
         public bool CanExportFrom(object obj)
         {
-            return gui.ApplicationCore.GetSupportedFileExporters(gui.Selection).Any();
+            return gui.ApplicationCore.GetSupportedFileExporters(obj).Any();
         }
 
         public bool CanShowPropertiesFor(object obj)
         {
-            return PropertyResolver.GetObjectProperties(gui.Plugins.SelectMany(p => p.GetPropertyInfos()).ToList(), gui.Selection) != null;
+            return PropertyResolver.GetObjectProperties(gui.Plugins.SelectMany(p => p.GetPropertyInfos()).ToList(), obj) != null;
         }
 
         public void ImportOn(object target, IFileImporter importer = null)
@@ -163,7 +163,7 @@
             }
             catch (Exception)
             {
-                Log.ErrorFormat(Resources.GuiCommandHandler_ImportOn_Unable_to_import_on_0_, gui.Selection);
+                Log.ErrorFormat(Resources.GuiCommandHandler_ImportOn_Unable_to_import_on_0_, target);
             }
         }
 
Index: Core/Common/src/Core.Common.Gui/Properties/Resources.Designer.cs
===================================================================
diff -u -r23773f2915c16d8f4d86b6bba06769ffc8e4032d -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Core/Common/src/Core.Common.Gui/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 23773f2915c16d8f4d86b6bba06769ffc8e4032d)
+++ Core/Common/src/Core.Common.Gui/Properties/Resources.Designer.cs	(.../Resources.Designer.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -1513,7 +1513,7 @@
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to NodePresenter_CommandHandler_required.
+        ///   Looks up a localized string similar to Voor het aanmaken van knopen in de boom is een CommandHandler nodig..
         /// </summary>
         public static string NodePresenter_CommandHandler_required {
             get {
Index: Core/Common/src/Core.Common.Gui/Properties/Resources.resx
===================================================================
diff -u -r23773f2915c16d8f4d86b6bba06769ffc8e4032d -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Core/Common/src/Core.Common.Gui/Properties/Resources.resx	(.../Resources.resx)	(revision 23773f2915c16d8f4d86b6bba06769ffc8e4032d)
+++ Core/Common/src/Core.Common.Gui/Properties/Resources.resx	(.../Resources.resx)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -879,7 +879,7 @@
     <value>Verwijder de knoop uit de boom.</value>
   </data>
   <data name="NodePresenter_CommandHandler_required" xml:space="preserve">
-    <value>NodePresenter_CommandHandler_required</value>
+    <value>Voor het aanmaken van knopen in de boom is een CommandHandler nodig.</value>
   </data>
   <data name="NodePresenter_ContextMenuBuilderProvider_required" xml:space="preserve">
     <value>Voor het aanmaken van knopen in de boom is een ContextMenuBuilderProvider nodig.</value>
Index: Core/Common/test/Core.Common.Gui.Test/ContextMenu/ContextMenuBuilderTest.cs
===================================================================
diff -u -r2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Core/Common/test/Core.Common.Gui.Test/ContextMenu/ContextMenuBuilderTest.cs	(.../ContextMenuBuilderTest.cs)	(revision 2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2)
+++ Core/Common/test/Core.Common.Gui.Test/ContextMenu/ContextMenuBuilderTest.cs	(.../ContextMenuBuilderTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Windows.Forms;
-using Core.Common.Base;
 using Core.Common.Controls;
 using Core.Common.Gui.ContextMenu;
 using Core.Common.Gui.Properties;
@@ -71,8 +70,20 @@
         public void AddDeleteItem_WhenBuild_ItemAddedToContextMenu()
         {
             // Setup
-            var builder = new ContextMenuBuilder(null, MockRepository.GenerateMock<ITreeNode>());
+            var treeNodePresenterMock = mocks.StrictMock<ITreeNodePresenter>();
+            var treeParentNodeMock = mocks.StrictMock<ITreeNode>();
+            var treeNodeMock = mocks.StrictMock<ITreeNode>();
 
+            treeNodeMock.Expect(tn => tn.Parent).Return(treeParentNodeMock);
+            treeNodeMock.Expect(tn => tn.Presenter).Return(treeNodePresenterMock);
+            treeNodeMock.Expect(tn => tn.Tag).Return(null);
+            treeParentNodeMock.Expect(tn => tn.Tag).Return(null);
+            treeNodePresenterMock.Expect(tn => tn.CanRemove(null,null)).Return(true);
+
+            mocks.ReplayAll();
+
+            var builder = new ContextMenuBuilder(null, treeNodeMock);
+
             // Call
             var result = builder.AddDeleteItem().Build();
 
Index: Core/Common/test/Core.Common.Gui.Test/GuiCommandHandlerTest.cs
===================================================================
diff -u -r2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Core/Common/test/Core.Common.Gui.Test/GuiCommandHandlerTest.cs	(.../GuiCommandHandlerTest.cs)	(revision 2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2)
+++ Core/Common/test/Core.Common.Gui.Test/GuiCommandHandlerTest.cs	(.../GuiCommandHandlerTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -15,13 +15,12 @@
         }
 
         [Test]
-        public void CanShowPropertiesForGuiSelection_PropertiesForObjectDefined_True()
+        public void CanShowPropertiesFor_PropertiesForObjectDefined_True()
         {
             // Setup
             var gui = mocks.DynamicMock<IGui>();
             var anObject = new AnObject();
             gui.Expect(g => g.Plugins).Return(new GuiPlugin[] {new TestGuiPlugin()});
-            gui.Expect(g => g.Selection).Return(anObject);
 
             mocks.ReplayAll();
 
@@ -37,13 +36,12 @@
         }
 
         [Test]
-        public void CanShowPropertiesForGuiSelection_PropertiesForSuperObjectDefined_True()
+        public void CanShowPropertiesFor_PropertiesForSuperObjectDefined_True()
         {
             // Setup
             var gui = mocks.DynamicMock<IGui>();
             var aSubObject = new ASubObject();
             gui.Expect(g => g.Plugins).Return(new GuiPlugin[] {new TestGuiPlugin()});
-            gui.Expect(g => g.Selection).Return(aSubObject);
 
             mocks.ReplayAll();
 
Index: Ringtoets/Common/test/Ringtoets.Common.Forms.Test/NodePresenters/CategoryTreeFolderNodePresenterTest.cs
===================================================================
diff -u -r2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Ringtoets/Common/test/Ringtoets.Common.Forms.Test/NodePresenters/CategoryTreeFolderNodePresenterTest.cs	(.../CategoryTreeFolderNodePresenterTest.cs)	(revision 2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2)
+++ Ringtoets/Common/test/Ringtoets.Common.Forms.Test/NodePresenters/CategoryTreeFolderNodePresenterTest.cs	(.../CategoryTreeFolderNodePresenterTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -45,7 +45,7 @@
         }
 
         [Test]
-        public void DefaultConstructor_ExpectedValues()
+        public void Constructor_ParamsSet_ExpectedValues()
         {
             // Call
             var contextMenuBuilderProviderMock = mockRepository.StrictMock<IContextMenuBuilderProvider>();
Index: Ringtoets/Common/test/Ringtoets.Common.Forms.Test/NodePresenters/RingtoetsNodePresenterBaseTest.cs
===================================================================
diff -u -rd02fa527769665fe275986468c6ac570fbad5e48 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Ringtoets/Common/test/Ringtoets.Common.Forms.Test/NodePresenters/RingtoetsNodePresenterBaseTest.cs	(.../RingtoetsNodePresenterBaseTest.cs)	(revision d02fa527769665fe275986468c6ac570fbad5e48)
+++ Ringtoets/Common/test/Ringtoets.Common.Forms.Test/NodePresenters/RingtoetsNodePresenterBaseTest.cs	(.../RingtoetsNodePresenterBaseTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -41,7 +41,7 @@
         }
 
         [Test]
-        public void DefaultConstructor_ExpectedValues()
+        public void Constructor_ParamsSet_ExpectedValues()
         {
             // Call
             var nodePresenter = new SimpleRingtoetsNodePresenterBase<double>(contextMenuBuilderProviderMock);
Index: Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/NodePresenters/FailureMechanismNodePresenterTest.cs
===================================================================
diff -u -r2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/NodePresenters/FailureMechanismNodePresenterTest.cs	(.../FailureMechanismNodePresenterTest.cs)	(revision 2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/NodePresenters/FailureMechanismNodePresenterTest.cs	(.../FailureMechanismNodePresenterTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Drawing;
 using System.Linq;
 using System.Windows.Forms;
@@ -36,9 +37,21 @@
         }
 
         [Test]
-        public void DefaultConstructor_ExpectedValues()
+        public void Constructor_NoMenuBuilderProvider_ArgumentNullException()
         {
             // Call
+            TestDelegate test = () => new FailureMechanismNodePresenter(null);
+
+            // Assert
+            var message = Assert.Throws<ArgumentNullException>(test).Message;
+            StringAssert.StartsWith(CommonResources.NodePresenter_ContextMenuBuilderProvider_required, message);
+            StringAssert.EndsWith("contextMenuBuilderProvider", message);
+        }
+
+        [Test]
+        public void Constructor_ParamsSet_ExpectedValues()
+        {
+            // Call
             var contextMenuProvider = mocks.StrictMock<IContextMenuBuilderProvider>();
             var nodePresenter = new FailureMechanismNodePresenter(contextMenuProvider);
 
Index: Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/NodePresenters/PlaceholderWithReadonlyNameNodePresenterTest.cs
===================================================================
diff -u -r2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/NodePresenters/PlaceholderWithReadonlyNameNodePresenterTest.cs	(.../PlaceholderWithReadonlyNameNodePresenterTest.cs)	(revision 2b9e80f0d003d30c57fae2f16f25acaf9b58d2d2)
+++ Ringtoets/Integration/test/Ringtoets.Integration.Forms.Test/NodePresenters/PlaceholderWithReadonlyNameNodePresenterTest.cs	(.../PlaceholderWithReadonlyNameNodePresenterTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -1,4 +1,5 @@
-using System.Collections;
+using System;
+using System.Collections;
 using System.Drawing;
 using System.Windows.Forms;
 using Core.Common.Base;
@@ -31,10 +32,22 @@
         {
             mocks = new MockRepository();
         }
-        
+
         [Test]
-        public void DefaultConstructor_ExpectedValues()
+        public void Constructor_NoMenuBuilderProvider_ArgumentNullException()
         {
+            // Call
+            TestDelegate test = () => new PlaceholderWithReadonlyNameNodePresenter(null);
+
+            // Assert
+            var message = Assert.Throws<ArgumentNullException>(test).Message;
+            StringAssert.StartsWith(CommonResources.NodePresenter_ContextMenuBuilderProvider_required, message);
+            StringAssert.EndsWith("contextMenuBuilderProvider", message);
+        }
+
+        [Test]
+        public void Constructor_ParamsSet_ExpectedValues()
+        {
             // Setup
             var contextMenuProvider = mocks.StrictMock<IContextMenuBuilderProvider>();
 
Index: Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/NodePresenters/PipingFailureMechanismNodePresenterTest.cs
===================================================================
diff -u -rf8c052756f1c460774495e8724a2d9e049564ff3 -r6aa508233ca39077a4a10ec8275619d61ddab47b
--- Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/NodePresenters/PipingFailureMechanismNodePresenterTest.cs	(.../PipingFailureMechanismNodePresenterTest.cs)	(revision f8c052756f1c460774495e8724a2d9e049564ff3)
+++ Ringtoets/Piping/test/Ringtoets.Piping.Forms.Test/NodePresenters/PipingFailureMechanismNodePresenterTest.cs	(.../PipingFailureMechanismNodePresenterTest.cs)	(revision 6aa508233ca39077a4a10ec8275619d61ddab47b)
@@ -55,7 +55,7 @@
         }
 
         [Test]
-        public void DefaultConstructor_ExpectedValues()
+        public void Constructor_ParamsSet_ExpectedValues()
         {
             // Setup
             var contextMenuBuilderProviderMock = mockRepository.StrictMock<IContextMenuBuilderProvider>();