so what you did was something like this:
--- a/program/js/editor.js 2017-10-15 07:34:57.004498382 +0100
+++ b/program/js/editor.js 2017-10-17 07:34:29.531100299 +0100
@@ -90,7 +90,7 @@
$.extend(conf, {
plugins: 'autolink charmap code colorpicker directionality link lists image media nonbreaking'
+ ' paste table tabfocus textcolor searchreplace spellchecker',
- toolbar: 'bold italic underline | alignleft aligncenter alignright alignjustify'
+ toolbar: 'strikethrough bold italic underline | alignleft aligncenter alignright alignjustify'
+ ' | bullist numlist outdent indent ltr rtl blockquote | forecolor backcolor | fontselect fontsizeselect'
+ ' | link unlink table | $extra charmap image media | code searchreplace undo redo',
spellchecker_rpc_url: abs_url + '/?_task=utils&_action=spell_html&_remote=1',
it works fine for me. I guess check where your browser is reading editor.js from and that in version your browser is using has the change in.