Install Ckeditor Plugin

How do I add and register a plugin in Ckeditor?

This plugin inserts a non breaking space via control+space on keyboard.

I followed the steps given in Ckeditor but i won’t work.

After downloading from ckeditor.com the plugin, I copy folder «nbsp» into:
concrete/js/ckeditor/plugins

then in concrete/js/ckeditor/config.js I add
config.extraPlugins = ‘nbsp’;

Since it’s very useful, I’d love to have this inserted via the editor interface as it used to be in the old old editor in v.5.6 There you had a small icon to click and the non breaking space was there.

Does anybody know? Or does anybody use another external plugin?

Thank you for insights.

You could try