diff --git a/Contrib/Modern UI/Readme.html b/Contrib/Modern UI/Readme.html
index b71c1697..1f4bf7b0 100644
--- a/Contrib/Modern UI/Readme.html	
+++ b/Contrib/Modern UI/Readme.html	
@@ -978,6 +978,9 @@ The text to display on the language selection dialog.</p>
 Always show the language selection dialog, even if a language has
 been stored in the registry. The language stored in the registry
 will be selected by default.</p>
+<p><strong>MUI_LANGDLL_SHOW_ALL_LANGUAGES</strong><br />
+Always show all available languages and don't filter according
+to their codepage.</p>
 </div>
 </div>
 </div>