I apologise in advance if I'm missing something here, but I'm stuck in attempts to configure tinyMCE for frontend editing with simple buttons setup without result.

Steps to reproduce the issue

(Fresh installation)
1.In Options for Users choose "Allow User Registration - Yes" and "New User Registration Group - Author"
2. Go to Plugins -> TinyMCE and configure it so the Simple set №2 with minimum number of buttons is assigned to "Author" group (see the screenshot attached). I've also removed for clarity of experiment "Registered" group from any sets (0,1,2) - http://take.ms/CTmVw
3. Register, activate a new user via frontend and try to create a new article in frontend with a default editor - TinyMCE

Expected result

Minimum number of buttons in UI of the editor as the setting implies

Actual result

Chosen setup plus other buttons - Module, Menu, Contact, Article, Image
An ordinary "Author" by default has access to a good number of internal site elements to see and even insert into his/her post which is wrong imo. Besides I couldn't figure out how to disable these buttons and appreciate it if you let me know.
http://take.ms/EWSvAI