After rename editor.css not working

I’m still having problem to show text editor in the topic replay and form. after changing the wp-includes/css/editor.css to editor-buttons.css

reference here
http://wordpress.org/support/topic/plugin-u-buddypress-forum-editor-not-working?replies=6

Please help me I’m using everything are latest version

http://wordpress.org/plugins/u-buddypress-forum-editor/