diff --git a/runtime/ftplugin/tutor.vim b/runtime/ftplugin/tutor.vim
index 5660cbf..92bca8d 100644
--- a/runtime/ftplugin/tutor.vim
+++ b/runtime/ftplugin/tutor.vim
@@ -6,21 +6,13 @@
 " Original Author: Felipe Morales <hel.sheep@gmail.com>
 " Last Change:
 " 2025 May 10 set b:undo_ftplugin
+" 2025 May 12 update b:undo_ftplugin
 
 " Base: {{{1
 call tutor#SetupVim()
 
 " Buffer Settings: {{{1
 setlocal noreadonly
-if !exists('g:tutor_debug') || g:tutor_debug == 0
-    setlocal buftype=nofile
-    setlocal concealcursor+=inv
-    setlocal conceallevel=2
-else
-    setlocal buftype=
-    setlocal concealcursor&
-    setlocal conceallevel=0
-endif
 setlocal noundofile
 
 setlocal keywordprg=:help
@@ -46,14 +38,7 @@
 sign define tutorok text=✓ texthl=tutorOK
 sign define tutorbad text=✗ texthl=tutorX
 
-if !exists('g:tutor_debug') || g:tutor_debug == 0
-    call tutor#ApplyMarks()
-    autocmd! TextChanged,TextChangedI <buffer> call tutor#ApplyMarksOnChanged()
-endif
-
-let b:undo_ftplugin = 'unlet! g:tutor_debug |'
-let b:undo_ftplugin ..= 'setl concealcursor< conceallevel< |'
-let b:undo_ftplugin ..= 'setl foldmethod< foldexpr< foldlevel< |'
-let b:undo_ftplugin ..= 'setl buftype< undofile< keywordprg< iskeyword< |'
+let b:undo_ftplugin = "setl foldmethod< foldexpr< foldlevel< undofile< keywordprg< iskeyword< |"
+    \ . "call tutor#EnableInteractive(v:false) |"
 
 " vim: fdm=marker