Form errors (highlight)

Hello,

How can I force the rails so that it would know which fields to
highlight when I use the selectbox for posting bad id to the server, for
instance:

Review Model:

class Review < ActiveRecord::Base
belongs_to :article

validates_presence_of :article #or :article_id ??
validates_associated :article
validates_existence_of :article

end

The View:

<% form_for @review do |f| %>

<%= f.label :article %>

<%=
f.collection_select(:article_id, Article.all, :id, :name, {:prompt =>
true})
%>

<% end %>

When I specify bad value to the select box, rails will only highlight
label (:article) and wont highlight the :article_id select box. How can
I force it / let it know that its the brother-field so that both would
be highlighted?

Thanks for help!