fix cubetree init crash.

App/wwwroot/HiAPI-docsite/sample/Sample.Disp.DemoUtil.html

@@ -157,40 +157,39 @@ using Hi.Licenses;
 using Hi.WpfPlus.Disp;
 using System.Windows;
 
-namespace Sample.Disp
+namespace Sample.Disp;
+
+/// <summary>
+/// Provides utility functions for running HiAPI display examples in a WPF environment.
+/// Contains helper methods that simplify the setup and execution of WPF applications with HiAPI rendering.
+/// Handles common initialization and cleanup tasks for visualization examples.
+/// </summary>
+/// <remarks>
+/// ### Source Code
+/// [!code-csharp[SampleCode](~/../Hi.Sample.Wpf/Disp/DemoUtil.cs)]
+/// </remarks>
+public static class DemoUtil
 {
     /// <summary>
-    /// Provides utility functions for running HiAPI display examples in a WPF environment.
-    /// Contains helper methods that simplify the setup and execution of WPF applications with HiAPI rendering.
-    /// Handles common initialization and cleanup tasks for visualization examples.
+    /// Creates and runs a WPF application with a RenderingWindow to display 3D content.
+    /// Handles proper initialization and cleanup of HiAPI resources including MongoDB server,
+    /// display engine, and licensing.
     /// </summary>
-    /// <remarks>
-    /// ### Source Code
-    /// [!code-csharp[SampleCode](~/../Hi.Sample.Wpf/Disp/DemoUtil.cs)]
-    /// </remarks>
-    public static class DemoUtil
+    /// <param name="title">The title for the application window</param>
+    /// <param name="displayee">The object that implements IDisplayee to be rendered</param>
+    public static void RunApplication(string title, IDisplayee displayee)
     {
-        /// <summary>
-        /// Creates and runs a WPF application with a RenderingWindow to display 3D content.
-        /// Handles proper initialization and cleanup of HiAPI resources including MongoDB server,
-        /// display engine, and licensing.
-        /// </summary>
-        /// <param name="title">The title for the application window</param>
-        /// <param name="displayee">The object that implements IDisplayee to be rendered</param>
-        public static void RunApplication(string title, IDisplayee displayee)
+        LocalApp.AppBegin();
+        Application app = new Application();
+        app.Exit += (o, e) =>
         {
-            LocalApp.AppBegin();
-            Application app = new Application();
-            app.Exit += (o, e) =>
-            {
-                LocalApp.AppEnd();
-            };
-            app.Run(new RenderingWindow()
-            {
-                Title = title,
-                Displayee = displayee
-            });
-        }
+            LocalApp.AppEnd();
+        };
+        app.Run(new RenderingWindow()
+        {
+            Title = title,
+            Displayee = displayee
+        });
     }
 }
 </code></pre></div>