diff --git a/ContextMenuManager/Controls/FileExtensionDialog.cs b/ContextMenuManager/Controls/FileExtensionDialog.cs
index f0f39ae..4396129 100644
--- a/ContextMenuManager/Controls/FileExtensionDialog.cs
+++ b/ContextMenuManager/Controls/FileExtensionDialog.cs
@@ -7,7 +7,6 @@ namespace ContextMenuManager.Controls
 {
     sealed class FileExtensionDialog : CommonDialog
     {
-        const string FileExtsPath = @"HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts";
         public string Extension { get; private set; }
         public override void Reset() { }
 
@@ -21,37 +20,6 @@ namespace ContextMenuManager.Controls
             }
         }
 
-        public static string GetTypeName(string extension, bool includeUWP = true)
-        {
-            using(var root = Microsoft.Win32.Registry.ClassesRoot)
-            {
-                bool TypeNameExists(string typeName)
-                {
-                    if(!string.IsNullOrEmpty(typeName))
-                        using(var typeKey = root.OpenSubKey(typeName))
-                            if(typeKey != null) return true;
-                    return false;
-                }
-
-                using(var extKey = root.OpenSubKey(extension))
-                {
-                    if(extKey == null) return null;
-                    string defaultType = extKey.GetValue("")?.ToString();
-                    if(TypeNameExists(defaultType)) return defaultType;
-                    using(var key = extKey.OpenSubKey("OpenWithProgids"))
-                    {
-                        if(key == null) return null;
-                        foreach(string valueName in key.GetValueNames())
-                        {
-                            if(!includeUWP && key.GetValueKind(valueName) != Microsoft.Win32.RegistryValueKind.String) continue;
-                            if(TypeNameExists(valueName)) return valueName;
-                        }
-                    }
-                }
-            }
-            return null;
-        }
-
         sealed class FileExtensionForm : Form
         {
             public FileExtensionForm()
@@ -68,16 +36,9 @@ namespace ContextMenuManager.Controls
                 LoadExtensions();
                 btnOk.Click += (sender, e) =>
                 {
-                    if(cmbExtension.Items.Contains(cmbExtension.Text))
-                    {
-                        this.Extension = $".{cmbExtension.Text}";
-                        this.DialogResult = DialogResult.OK;
-                    }
-                    else
-                    {
-                        MessageBoxEx.Show(AppString.MessageBox.UnsupportedExtension);
-                        cmbExtension.Focus();
-                    }
+                    int index = cmbExtension.Text.IndexOf('.');
+                    if(index >= 0) this.Extension = cmbExtension.Text.Substring(index);
+                    else this.Extension = $".{cmbExtension.Text}";
                 };
             }
 
@@ -87,10 +48,12 @@ namespace ContextMenuManager.Controls
             {
                 AutoCompleteMode = AutoCompleteMode.SuggestAppend,
                 AutoCompleteSource = AutoCompleteSource.ListItems,
-                DropDownHeight = 294.DpiZoom()
+                DropDownHeight = 294.DpiZoom(),
+                ImeMode = ImeMode.Disable
             };
             readonly Button btnOk = new Button
             {
+                DialogResult = DialogResult.OK,
                 Text = AppString.Dialog.Ok,
                 AutoSize = true
             };
@@ -103,26 +66,22 @@ namespace ContextMenuManager.Controls
 
             private void InitializeComponents()
             {
-                this.ClientSize = new Size(316, 110).DpiZoom();
                 this.Controls.AddRange(new Control[] { cmbExtension, btnOk, btnCancel });
                 int a = 20.DpiZoom();
                 cmbExtension.Left = a;
                 cmbExtension.Width = 85.DpiZoom();
-                cmbExtension.Top = btnOk.Top = btnCancel.Top = 2 * a;
+                cmbExtension.Top = btnOk.Top = btnCancel.Top = a;
                 btnOk.Left = cmbExtension.Right + a;
                 btnCancel.Left = btnOk.Right + a;
+                this.ClientSize = new Size(btnCancel.Right + a, btnCancel.Bottom + a);
             }
 
             private void LoadExtensions()
             {
-                using(var extKey = RegistryEx.GetRegistryKey(FileExtsPath))
+                foreach(string extension in Microsoft.Win32.Registry.ClassesRoot.GetSubKeyNames())
                 {
-                    if(extKey == null) return;
-                    foreach(string extension in extKey.GetSubKeyNames())
-                    {
-                        if(!extension.StartsWith(".") || GetTypeName(extension) == null) continue;
-                        cmbExtension.Items.Add(extension.Substring(1));
-                    }
+                    if(!extension.StartsWith(".")) continue;
+                    cmbExtension.Items.Add(extension.Substring(1));
                 }
             }
         }