diff --git a/runtime/ftplugin/muttrc.vim b/runtime/ftplugin/muttrc.vim
index 18b06d8..a109e5d 100644
--- a/runtime/ftplugin/muttrc.vim
+++ b/runtime/ftplugin/muttrc.vim
@@ -8,9 +8,15 @@
 endif
 let b:did_ftplugin = 1
 
+let s:cpo_save = &cpo
+set cpo&vim
+
 let b:undo_ftplugin = "setl com< cms< inc< fo<"
 
 setlocal comments=:# commentstring=#\ %s
 setlocal formatoptions-=t formatoptions+=croql
 
 let &l:include = '^\s*source\>'
+
+let &cpo = s:cpo_save
+unlet s:cpo_save