diff --git a/runtime/ftplugin/m3build.vim b/runtime/ftplugin/m3build.vim
index 9e1e169..c910eae 100644
--- a/runtime/ftplugin/m3build.vim
+++ b/runtime/ftplugin/m3build.vim
@@ -1,21 +1,20 @@
 " Vim filetype plugin file
 " Language:	Modula-3 Makefile
 " Maintainer:	Doug Kearns <dougkearns@gmail.com>
-" Last Change:	2021 April 15
+" Last Change:	2022 June 12
 
 if exists("b:did_ftplugin")
   finish
 endif
-let b:did_ftplugin = 1
 
 let s:cpo_save = &cpo
 set cpo&vim
 
 runtime! ftplugin/m3quake.vim
 
-if (has("gui_win32") || has("gui_gtk")) && !exists("b:browsefilter")
-  let b:browsefilter = "Modula-3 Makefile (m3makefile m3overrides)\tm3makefile;m3overrides\n" ..
-	\	       "All Files (*.*)\t*.*\n"
+if (has("gui_win32") || has("gui_gtk")) && exists("b:m3quake_set_browsefilter")
+    let b:browsefilter = "Modula-3 Makefile (m3makefile m3overrides)\tm3makefile;m3overrides\n" ..
+	  \		 "All Files (*.*)\t*.*\n"
 endif
 
 let &cpo = s:cpo_save