Index: Ringtoets/Common/src/Ringtoets.Common.Forms/Factories/RingtoetsMapDataFeaturesFactory.cs
===================================================================
diff -u -r16559315c0a64fffd05827d249200c62e353231f -rdf5853e34e5c42f878c5ceccdada111743837ba4
--- Ringtoets/Common/src/Ringtoets.Common.Forms/Factories/RingtoetsMapDataFeaturesFactory.cs	(.../RingtoetsMapDataFeaturesFactory.cs)	(revision 16559315c0a64fffd05827d249200c62e353231f)
+++ Ringtoets/Common/src/Ringtoets.Common.Forms/Factories/RingtoetsMapDataFeaturesFactory.cs	(.../RingtoetsMapDataFeaturesFactory.cs)	(revision df5853e34e5c42f878c5ceccdada111743837ba4)
@@ -100,11 +100,16 @@
         /// </summary>
         /// <param name="hydraulicBoundaryDatabase">The <see cref="HydraulicBoundaryDatabase"/>
         /// to create the location features for.</param>
-        /// <returns>A collection of features or an empty collection when <paramref name="hydraulicBoundaryDatabase"/> 
-        /// is <c>null</c>.</returns>
+        /// <returns>A collection of features.</returns>
+        /// <exception cref="ArgumentNullException">Thrown when <paramref name="hydraulicBoundaryDatabase"/> is <c>null</c>.</exception>
         public static IEnumerable<MapFeature> CreateHydraulicBoundaryDatabaseFeatures(HydraulicBoundaryDatabase hydraulicBoundaryDatabase)
         {
-            return CreateHydraulicBoundaryLocationFeatures(hydraulicBoundaryDatabase?.Locations.ToArray() ?? new HydraulicBoundaryLocation[0],
+            if (hydraulicBoundaryDatabase == null)
+            {
+                throw new ArgumentNullException(nameof(hydraulicBoundaryDatabase));
+            }
+
+            return CreateHydraulicBoundaryLocationFeatures(hydraulicBoundaryDatabase.Locations.ToArray(),
                                                            Resources.DesignWaterLevel_DisplayName,
                                                            Resources.MetaData_WaveHeight);
         }
Index: Ringtoets/Integration/src/Ringtoets.Integration.Plugin/RingtoetsPlugin.cs
===================================================================
diff -u -rffba5900acc192187346a9ad73acea5e8b9d0bf5 -rdf5853e34e5c42f878c5ceccdada111743837ba4
--- Ringtoets/Integration/src/Ringtoets.Integration.Plugin/RingtoetsPlugin.cs	(.../RingtoetsPlugin.cs)	(revision ffba5900acc192187346a9ad73acea5e8b9d0bf5)
+++ Ringtoets/Integration/src/Ringtoets.Integration.Plugin/RingtoetsPlugin.cs	(.../RingtoetsPlugin.cs)	(revision df5853e34e5c42f878c5ceccdada111743837ba4)
@@ -372,7 +372,7 @@
             yield return new ViewInfo<DesignWaterLevelLocationsContext, IEnumerable<HydraulicBoundaryLocation>, DesignWaterLevelLocationsView>
             {
                 GetViewName = (view, context) => RingtoetsFormsResources.DesignWaterLevelLocationsContext_DisplayName,
-                GetViewData = context => context.WrappedData.HydraulicBoundaryDatabase?.Locations,
+                GetViewData = context => context.WrappedData.HydraulicBoundaryDatabase.Locations,
                 Image = RingtoetsCommonFormsResources.GenericInputOutputIcon,
                 CloseForData = CloseHydraulicBoundaryLocationsViewForData,
                 CreateInstance = context => new DesignWaterLevelLocationsView(context.WrappedData),
@@ -382,7 +382,7 @@
             yield return new ViewInfo<WaveHeightLocationsContext, IEnumerable<HydraulicBoundaryLocation>, WaveHeightLocationsView>
             {
                 GetViewName = (view, context) => RingtoetsFormsResources.WaveHeightLocationsContext_DisplayName,
-                GetViewData = context => context.WrappedData.HydraulicBoundaryDatabase?.Locations,
+                GetViewData = context => context.WrappedData.HydraulicBoundaryDatabase.Locations,
                 Image = RingtoetsCommonFormsResources.GenericInputOutputIcon,
                 CloseForData = CloseHydraulicBoundaryLocationsViewForData,
                 CreateInstance = context => new WaveHeightLocationsView(context.WrappedData),
@@ -516,7 +516,7 @@
                 CreateFileExporter = (context, filePath) => new HydraulicBoundaryLocationsExporter(
                     context.WrappedData.HydraulicBoundaryDatabase.Locations, filePath,
                     RingtoetsIntegrationPluginResources.DesignWaterLevel_Description, RingtoetsIntegrationPluginResources.WaveHeight_Description),
-                IsEnabled = context => context.WrappedData.HydraulicBoundaryDatabase != null,
+                IsEnabled = context => context.WrappedData.HydraulicBoundaryDatabase.IsCoupled(),
                 FileFilterGenerator = new FileFilterGenerator(RingtoetsCommonIOResources.Shape_file_filter_Extension,
                                                               RingtoetsCommonIOResources.Shape_file_filter_Description)
             };
@@ -654,9 +654,9 @@
             {
                 Text = hydraulicBoundaryDatabase => RingtoetsFormsResources.HydraulicBoundaryDatabase_DisplayName,
                 Image = hydraulicBoundaryDatabase => RingtoetsCommonFormsResources.GenericInputOutputIcon,
-                ForeColor = context => context.WrappedData.HydraulicBoundaryDatabase == null
-                                           ? Color.FromKnownColor(KnownColor.GrayText)
-                                           : Color.FromKnownColor(KnownColor.ControlText),
+                ForeColor = context => context.WrappedData.HydraulicBoundaryDatabase.IsCoupled()
+                                           ? Color.FromKnownColor(KnownColor.ControlText)
+                                           : Color.FromKnownColor(KnownColor.GrayText),
                 ChildNodeObjects = HydraulicBoundaryDatabaseChildNodeObjects,
                 ContextMenuStrip = HydraulicBoundaryDatabaseContextMenuStrip
             };
@@ -1376,15 +1376,16 @@
 
         private static object[] HydraulicBoundaryDatabaseChildNodeObjects(HydraulicBoundaryDatabaseContext nodeData)
         {
-            if (nodeData.WrappedData.HydraulicBoundaryDatabase == null)
+            if (nodeData.WrappedData.HydraulicBoundaryDatabase.IsCoupled())
             {
-                return new object[0];
+                return new object[]
+                {
+                    new DesignWaterLevelLocationsContext(nodeData.WrappedData),
+                    new WaveHeightLocationsContext(nodeData.WrappedData)
+                };
             }
-            return new object[]
-            {
-                new DesignWaterLevelLocationsContext(nodeData.WrappedData),
-                new WaveHeightLocationsContext(nodeData.WrappedData)
-            };
+
+            return new object[0];
         }
 
         private ContextMenuStrip DesignWaterLevelLocationsContextMenuStrip(DesignWaterLevelLocationsContext nodeData, object parentData, TreeViewControl treeViewControl)
@@ -1523,29 +1524,25 @@
         {
             HydraulicBoundaryDatabase hydraulicBoundaryDatabase = assessmentSection.HydraulicBoundaryDatabase;
 
-            bool isHydraulicBoundaryDatabaseSet = hydraulicBoundaryDatabase != null;
-            bool isClearConfirmationRequired = isHydraulicBoundaryDatabaseSet && !HydraulicBoundaryDatabaseHelper.HaveEqualVersion(hydraulicBoundaryDatabase, databaseFile);
-            bool isClearConfirmationGiven = isClearConfirmationRequired && IsClearCalculationConfirmationGiven();
-
-            if (isHydraulicBoundaryDatabaseSet && isClearConfirmationRequired && !isClearConfirmationGiven)
+            bool haveEqualVersion = HydraulicBoundaryDatabaseHelper.HaveEqualVersion(hydraulicBoundaryDatabase, databaseFile);
+            bool isClearConfirmationRequired = hydraulicBoundaryDatabase.IsCoupled() && !haveEqualVersion;
+            if (isClearConfirmationRequired && !IsClearCalculationConfirmationGiven())
             {
                 return;
             }
 
-            HydraulicBoundaryDatabase previousHydraulicBoundaryDatabase = assessmentSection.HydraulicBoundaryDatabase;
             using (var hydraulicBoundaryLocationsImporter = new HydraulicBoundaryDatabaseImporter())
             {
                 if (hydraulicBoundaryLocationsImporter.Import(assessmentSection, databaseFile))
                 {
-                    if (isClearConfirmationGiven)
+                    if (isClearConfirmationRequired)
                     {
                         ClearCalculations(assessmentSection);
                     }
 
-                    if (!ReferenceEquals(previousHydraulicBoundaryDatabase, assessmentSection.HydraulicBoundaryDatabase))
+                    if (!haveEqualVersion)
                     {
-                        HydraulicBoundaryLocation[] hydraulicBoundaryLocations = assessmentSection.HydraulicBoundaryDatabase?.Locations.ToArray()
-                                                                                 ?? new HydraulicBoundaryLocation[0];
+                        HydraulicBoundaryLocation[] hydraulicBoundaryLocations = assessmentSection.HydraulicBoundaryDatabase.Locations.ToArray();
 
                         assessmentSection.GrassCoverErosionOutwards.SetGrassCoverErosionOutwardsHydraulicBoundaryLocations(hydraulicBoundaryLocations);
                         assessmentSection.GrassCoverErosionOutwards.HydraulicBoundaryLocations.NotifyObservers();
@@ -1556,6 +1553,7 @@
 
                         assessmentSection.DuneErosion.DuneLocations.NotifyObservers();
                     }
+
                     log.InfoFormat(RingtoetsFormsResources.RingtoetsPlugin_SetBoundaryDatabaseFilePath_Database_on_path_0_linked,
                                    assessmentSection.HydraulicBoundaryDatabase.FilePath);
                 }