SOLVED Plugin dev. routing

[mica]

Are you use get_page_content(); in your theme?

Yep ; )

Ok guys I made a fresh install and the solution of Bigin works there. Probably too much plugins added/removed on my local version
here is the final code 
route : galleries/([a-z0-9-/]+)
action : 

PHP Code:

<?php

return array( 'title' => 'My Title '.$args[0], 
   'content' => function($slug) {
    get_page_slug(false);  (now if I comment this line it still work)
   echo 'This is my Gallery ' .$slug;

}); 


Thank you to both of you for your time and the sharing of your knowledge !