Seems like there is a bug in bolded block, or i don't understend logic of it's creators.

# File vendor/rails/actionpack/lib/action_view/helpers/url_helper.rb, line 518
518:       def current_page?(options)
519:         url_string = CGI.escapeHTML(url_for(options))
520:         request = @controller.request
521:         # We ignore any extra parameters in the request_uri if the 
522:         # submitted url doesn't have any either.  This lets the function
523:         # work with things like ?order=asc 
524:         **if url_string.index("?") **
525:            **request_uri = request.request_uri**
526:          **else **
527:           **request_uri = request.request_uri.split('?').first**
528:          **end**
529:         if url_string =~ /^\w+:\/\//
530:           url_string == "#{request.protocol}#{request.host_with_port}#{request_uri}"
531:         else
532:           url_string == request_uri
533:         end
534:       end