diff --git a/ext/tk/sample/tkcombobox.rb b/ext/tk/sample/tkcombobox.rb
index 1840270951..cc51a2ffeb 100644
--- a/ext/tk/sample/tkcombobox.rb
+++ b/ext/tk/sample/tkcombobox.rb
@@ -219,6 +219,16 @@ EOD
   end
 end
 
+################################################
+
+# don't use Ttk widget
+Object.instance_eval{remove_const :TkCombobox} if Object.autoload? :TkCombobox
+
+# if you want to use the 'default_widget_set' selector, 
+#class TkCombobox < TkEntry; end
+#Tk.__set_toplevel_aliases__(:Tk, TkCombobox, :TkCombobox)
+
+
 ################################################
 
 class TkCombobox < TkEntry