[3.2] route issue w root url displayed

Rails
#1

my app has scoped routes :

MyApp::Application.routes.draw do

scope “/:locale” do
…
…
end

root :to => “cms_content#render_html”, :defaults => { :locale =>
I18n.locale }
end

I also have an helper to preset the locale for all my routes :

def default_url_options(options={})
{ :locale => I18n.locale }
end
so all urls are generated like :
http://www.mydomain.com/en/users
…

but for the root url
it generates :
http://www.mydomain.com/?locale=en
which is correctly handled by my app , but not so nice displayed …

I’d prefer to see the root url being :
http://www.mydomain.com/en/

is there anyway to get it ?