diff --git a/runtime/ftplugin/m3quake.vim b/runtime/ftplugin/m3quake.vim
index 627aabd..7762875 100644
--- a/runtime/ftplugin/m3quake.vim
+++ b/runtime/ftplugin/m3quake.vim
@@ -1,7 +1,7 @@
 " Vim filetype plugin file
 " Language:	Modula-3 Quake
 " Maintainer:	Doug Kearns <dougkearns@gmail.com>
-" Last Change:	2021 April 15
+" Last Change:	2022 June 12
 
 if exists("b:did_ftplugin")
   finish
@@ -15,18 +15,20 @@
 setlocal commentstring=%\ %s
 setlocal formatoptions-=t formatoptions+=croql
 
+let b:undo_ftplugin = "setl fo< com< cms<"
+
 if exists("loaded_matchit") && !exists("b:match_words")
   let b:match_words = '\<\%(proc\|if\|foreach\)\>:\<else\>:\<end\>'
+  let b:undo_ftplugin ..= " | unlet! b:match_words"
 endif
 
 if (has("gui_win32") || has("gui_gtk")) && !exists("b:browsefilter")
   let b:browsefilter = "Modula-3 Quake Source Files (*.quake)\t*.quake\n" ..
 	\	       "All Files (*.*)\t*.*\n"
+  let b:m3quake_set_browsefilter = 1
+  let b:undo_ftplugin ..= " | unlet! b:browsefilter b:m3quake_set_browsefilter"
 endif
 
-let b:undo_ftplugin = "setl fo< com< cms< " ..
-      \		      "| unlet! b:browsefilter b:match_words"
-
 let &cpo = s:cpo_save
 unlet s:cpo_save