Index: Ringtoets/Demo/src/Ringtoets.Demo/Commands/AddNewDemoDuneAssessmentSectionCommand.cs
===================================================================
diff -u -re8aaaf3808e54e4f075eab6f6c58bedf35e0890e -rd1a8aeaa05c36dfe386de7586dd129819594ee97
--- Ringtoets/Demo/src/Ringtoets.Demo/Commands/AddNewDemoDuneAssessmentSectionCommand.cs	(.../AddNewDemoDuneAssessmentSectionCommand.cs)	(revision e8aaaf3808e54e4f075eab6f6c58bedf35e0890e)
+++ Ringtoets/Demo/src/Ringtoets.Demo/Commands/AddNewDemoDuneAssessmentSectionCommand.cs	(.../AddNewDemoDuneAssessmentSectionCommand.cs)	(revision d1a8aeaa05c36dfe386de7586dd129819594ee97)
@@ -1,31 +1,32 @@
 using Core.Common.Gui;
-
 using Ringtoets.Integration.Data;
 
 namespace Ringtoets.Demo.Commands
 {
     /// <summary>
     /// Command that adds a new <see cref="DuneAssessmentSection"/> with demo data to the project tree.
     /// </summary>
-    public class AddNewDemoDuneAssessmentSectionCommand : GuiCommand
+    public class AddNewDemoDuneAssessmentSectionCommand : IGuiCommand
     {
-        public override bool Enabled
+        public bool Enabled
         {
             get
             {
                 return true;
             }
         }
 
-        public override bool Checked
+        public bool Checked
         {
             get
             {
                 return false;
             }
         }
 
-        public override void Execute(params object[] arguments)
+        public IGui Gui { get; set; }
+
+        public void Execute(params object[] arguments)
         {
             var project = Gui.Project;
             project.Items.Add(CreateNewDemoAssessmentSection());