[Fixed] – Bootstrap style : content section not taking 100% width when no side menu

Title is quite self explanatory but to provide more input, main content section stays in col-sm-9 style even if side menu ( secondary in my case ) is empty.

Visually it is quite obvious to notice : http://77beauval.net/_pit/agenda

Has this behaviour been noticed ?

Thx,

Drupal version: 


Source: https://www.drupal.org/taxonomy/term/3/feed