diff --git a/runtime/autoload/tutor.vim b/runtime/autoload/tutor.vim
index 3265fdd..6ab7960 100644
--- a/runtime/autoload/tutor.vim
+++ b/runtime/autoload/tutor.vim
@@ -210,6 +210,7 @@
 
     call tutor#SetupVim()
     exe "edit ".l:to_open
+    call tutor#EnableInteractive(v:true)
 endfunction
 
 function! tutor#TutorCmdComplete(lead,line,pos)
@@ -217,3 +218,24 @@
     let l:names = uniq(sort(map(l:tutors, 'fnamemodify(v:val, ":t:r")'), 's:Sort'))
     return join(l:names, "\n")
 endfunction
+
+" Enables/disables interactive mode.
+function! tutor#EnableInteractive(enable)
+    let enable = a:enable
+    if enable
+        setlocal buftype=nofile
+        setlocal concealcursor+=inv
+        setlocal conceallevel=2
+        call tutor#ApplyMarks()
+        augroup tutor_interactive
+            autocmd! TextChanged,TextChangedI <buffer> call tutor#ApplyMarksOnChanged()
+        augroup END
+    else
+        setlocal buftype<
+        setlocal concealcursor<
+        setlocal conceallevel<
+        if exists('#tutor_interactive')
+            autocmd! tutor_interactive * <buffer>
+        endif
+    endif
+endfunction