Index: Riskeer/Integration/src/Riskeer.Integration.Plugin/RiskeerPlugin.cs
===================================================================
diff -u -r436131a6956e94ebfd9ce917a4e8c9c307f662fb -rbbdeb25d8b1857b3fc69049808136a764a844448
--- Riskeer/Integration/src/Riskeer.Integration.Plugin/RiskeerPlugin.cs	(.../RiskeerPlugin.cs)	(revision 436131a6956e94ebfd9ce917a4e8c9c307f662fb)
+++ Riskeer/Integration/src/Riskeer.Integration.Plugin/RiskeerPlugin.cs	(.../RiskeerPlugin.cs)	(revision bbdeb25d8b1857b3fc69049808136a764a844448)
@@ -179,7 +179,7 @@
             {
                 if (project is RiskeerProject riskeerProject)
                 {
-                    AssessmentSection assessmentSection = riskeerProject.AssessmentSections.First();
+                    AssessmentSection assessmentSection = riskeerProject.AssessmentSection;
 
                     return new AssessmentSectionStateRootContext(assessmentSection);
                 }
@@ -191,7 +191,7 @@
             {
                 if (project is RiskeerProject riskeerProject)
                 {
-                    return new HydraulicLoadsStateRootContext(riskeerProject.AssessmentSections.First());
+                    return new HydraulicLoadsStateRootContext(riskeerProject.AssessmentSection);
                 }
 
                 return null;
@@ -201,7 +201,7 @@
             {
                 if (project is RiskeerProject riskeerProject)
                 {
-                    return new CalculationsStateRootContext(riskeerProject.AssessmentSections.First());
+                    return new CalculationsStateRootContext(riskeerProject.AssessmentSection);
                 }
 
                 return null;
@@ -211,7 +211,7 @@
             {
                 if (project is RiskeerProject riskeerProject)
                 {
-                    return new FailurePathsStateRootContext(riskeerProject.AssessmentSections.First());
+                    return new FailurePathsStateRootContext(riskeerProject.AssessmentSection);
                 }
 
                 return null;
@@ -885,9 +885,9 @@
         {
             if (viewData is RiskeerProject project)
             {
-                foreach (AssessmentSection item in project.AssessmentSections)
+                if (project.AssessmentSection != null)
                 {
-                    yield return item;
+                    yield return project.AssessmentSection;
                 }
             }
 
@@ -1348,8 +1348,8 @@
                 return;
             }
 
-            IEnumerable<AssessmentSection> sectionsWithHydraulicBoundaryDatabaseLinked = riskeerProject.AssessmentSections.Where(i => i.HydraulicBoundaryDatabase.IsLinked());
-            foreach (AssessmentSection section in sectionsWithHydraulicBoundaryDatabaseLinked)
+            AssessmentSection section = riskeerProject.AssessmentSection;
+            if (section != null && section.HydraulicBoundaryDatabase.IsLinked())
             {
                 string validationProblem = HydraulicBoundaryDatabaseHelper.ValidateFilesForCalculation(
                     section.HydraulicBoundaryDatabase.FilePath,
Index: Riskeer/Integration/test/Riskeer.Integration.Plugin.Test/RiskeerPluginTest.cs
===================================================================
diff -u -r79d532885abad824d867c39b42ac3a6598aefbcc -rbbdeb25d8b1857b3fc69049808136a764a844448
--- Riskeer/Integration/test/Riskeer.Integration.Plugin.Test/RiskeerPluginTest.cs	(.../RiskeerPluginTest.cs)	(revision 79d532885abad824d867c39b42ac3a6598aefbcc)
+++ Riskeer/Integration/test/Riskeer.Integration.Plugin.Test/RiskeerPluginTest.cs	(.../RiskeerPluginTest.cs)	(revision bbdeb25d8b1857b3fc69049808136a764a844448)
@@ -100,10 +100,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        new AssessmentSection(AssessmentSectionComposition.Dike)
-                    }
+                    AssessmentSection = new AssessmentSection(AssessmentSectionComposition.Dike)
                 };
 
                 // When
@@ -146,10 +143,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 // When
@@ -182,14 +176,11 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
+                    AssessmentSection = new AssessmentSection(AssessmentSectionComposition.Dike)
                     {
-                        new AssessmentSection(AssessmentSectionComposition.Dike)
+                        HydraulicBoundaryDatabase =
                         {
-                            HydraulicBoundaryDatabase =
-                            {
-                                FilePath = nonExistingFile
-                            }
+                            FilePath = nonExistingFile
                         }
                     }
                 };
@@ -721,19 +712,22 @@
         public void GetChildDataWithViewDefinitions_ProjectWithChildren_ReturnChildren()
         {
             // Setup
-            var project = new RiskeerProject();
-            project.AssessmentSections.Add(new AssessmentSection(AssessmentSectionComposition.Dike));
-            project.AssessmentSections.Add(new AssessmentSection(AssessmentSectionComposition.Dike));
-            project.AssessmentSections.Add(new AssessmentSection(AssessmentSectionComposition.Dike));
+            var assessmentSection = new AssessmentSection(AssessmentSectionComposition.Dike);
+            var project = new RiskeerProject
+            {
+                AssessmentSection = assessmentSection
+            };
 
             using (var plugin = new RiskeerPlugin())
             {
                 // Call
                 IEnumerable<object> childrenWithViewDefinitions = plugin.GetChildDataWithViewDefinitions(project);
 
                 // Assert
-                List<AssessmentSection> expectedResult = project.AssessmentSections;
-                CollectionAssert.AreEquivalent(expectedResult, childrenWithViewDefinitions);
+                CollectionAssert.AreEquivalent(new[]
+                {
+                    project.AssessmentSection
+                }, childrenWithViewDefinitions);
             }
         }
 
@@ -833,10 +827,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -901,10 +892,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -961,10 +949,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1021,10 +1006,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1076,10 +1058,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1133,10 +1112,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1190,10 +1166,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1244,10 +1217,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1301,10 +1271,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1358,10 +1325,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1415,10 +1379,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);
@@ -1469,10 +1430,7 @@
 
                 var project = new RiskeerProject
                 {
-                    AssessmentSections =
-                    {
-                        assessmentSection
-                    }
+                    AssessmentSection = assessmentSection
                 };
 
                 gui.SetProject(project, null);