Today I was trying to improve on the way error messages are displayed on a form. Instead of using error_messages_for at the top of the page, I want to put them next to the field with the problem.
Looking through the index of my beta copy of your book I could not see anything about this. I can see that you have to limit the size of the book, but most real life customers will want to see error messages inline.
I made some progress using Ryan Heath’s form_assistant plugin (http://rpheath.com/posts/359-rails-plugin-form-assistant), he provides partials for each field type, but as yet I could not find the model object and field name in scope within his partials to query the errors hash.
So my suggestion is (because I know you have loads of spare time), inline errors on forms !
I must be missing something because this should not be hard to do.