diff --git a/runtime/ftplugin/readline.vim b/runtime/ftplugin/readline.vim
index c81d0f2..a696da2 100644
--- a/runtime/ftplugin/readline.vim
+++ b/runtime/ftplugin/readline.vim
@@ -42,7 +42,7 @@
   if exists(':Sman') == 2
     setlocal iskeyword+=-
     setlocal keywordprg=:Sman
-    let b:undo_ftplugin .= '| setlocal keywordprg< iskeyword<'
+    let b:undo_ftplugin .= '| setlocal keywordprg< iskeyword< | sil! delc -buffer Sman'
   endif
 endif