diff --git a/SpineViewer/Natives/Shell32.cs b/SpineViewer/Natives/Shell32.cs
index a53286c..1a08aa6 100644
--- a/SpineViewer/Natives/Shell32.cs
+++ b/SpineViewer/Natives/Shell32.cs
@@ -14,10 +14,15 @@ namespace SpineViewer.Natives
     /// </summary>
     public static class Shell32
     {
-        public const uint SHCNE_ASSOCCHANGED = 0x08000000;
-        public const uint SHCNF_IDLIST = 0x0000;
+        private const uint SHCNE_ASSOCCHANGED = 0x08000000;
+        private const uint SHCNF_IDLIST = 0x0000;
 
         [DllImport("shell32.dll")]
-        public static extern void SHChangeNotify(uint wEventId, uint uFlags, IntPtr dwItem1, IntPtr dwItem2);
+        private static extern void SHChangeNotify(uint wEventId, uint uFlags, IntPtr dwItem1, IntPtr dwItem2);
+
+        public static void NotifyAssociationChanged()
+        {
+            SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, IntPtr.Zero, IntPtr.Zero);
+        }
     }
 }
diff --git a/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs b/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs
index 950c304..a5e3adc 100644
--- a/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs
+++ b/SpineViewer/ViewModels/MainWindow/PreferenceViewModel.cs
@@ -310,7 +310,7 @@ namespace SpineViewer.ViewModels.MainWindow
                         Registry.CurrentUser.DeleteSubKeyTree($@"Software\Classes\{App.ProgId}", false);
                     }
 
-                    Shell32.SHChangeNotify(Shell32.SHCNE_ASSOCCHANGED, Shell32.SHCNF_IDLIST, IntPtr.Zero, IntPtr.Zero);
+                    Shell32.NotifyAssociationChanged();
                 });
             }
         }