Correct me if I'm wrong, but if a callback is specified for render :json, the response is no longer json - it's javascript. Shouldn't the content type be set accordingly?
I'm experimenting with modifying the javascript response in an after_filter - for instance, I might append something along the lines of "Flash.show(#{flash[:notice]})" to display a flash regardless of whether the request was ajaxy or not. I could do the same with json by adding a 'flash' property to the json object, but only if I could be sure that the response really is pure json... hence this post.
