gistfile1.rb

module ActiveAdmin
  class FormBuilder < ::Formtastic::FormBuilder
    # ...

    # The input method returns a properly formatted string for
    # its contents, so we want to skip the internal buffering
    # while building up its contents
    def input(method, *args)
      content = with_new_form_buffer { super }
      return content.html_safe unless @inputs_with_block
      form_buffers.last << content.html_safe
    end

    # ...

    private

    def with_new_form_buffer
      form_buffers << "".html_safe
      return_value = yield
      form_buffers.pop
      return_value
    end
  end
end