The in_place_select_editor method assumes that you want to display the exact item being edited. That isn’t always the case. You might want to display a related attribute. The following modifies in_place_select_editor_field by allowing it to take a display parameter (third parameter), which is then passed to to_content_tag_display (also modified)

module ApplicationHelper

  def in_place_select_editor(field_id, options = {})

    function =  "new Ajax.InPlaceSelectEditor("
    function << "'#{field_id}', "

    function << "'#{url_for(options[:url])}'"
    function << (', ' + options_for_javascript(

       {
         'selectOptionsHTML' =>
                %('#{escape_javascript(options[:select_options].gsub(/n/, ""))}')

       }
       )
    ) if options[:select_options]
    function << ')'

    javascript_tag(function)
  end

  def in_place_select_editor_field(object, method, display, tag_options = {},
                                   in_place_editor_options = {})

    tag = ::ActionView::Helpers::InstanceTag.new(object, method, self)

    tag_options = { :tag => "span",
                    :id => "#{object}_#{method}_#{tag.object.id}_in_place_editor",
                   :class => "in_place_editor_field"}.merge!(tag_options)

    in_place_editor_options[:url] =
       in_place_editor_options[:url] ||
       url_for({ :action => "set_#{object}_#{method}", :id => tag.object.id })

    tag.to_content_tag_display(tag_options.delete(:tag), display, tag_options) +

    in_place_select_editor(tag_options[:id], in_place_editor_options)
  end

end

module ActionView
module Helpers

    class InstanceTag #:nodoc:
      include Helpers::TagHelper

      def to_content_tag_display(tag_name, display, options = {})

        content_tag(tag_name, display, options)
      end

    end

end
end

This permits (example), where Job.vendor_name(@job) (a custom method) is displayed.

            <%= in_place_select_editor_field(
             :job,
             :vendor_id,
             Job.vendor_name(@job),
             {},
             :select_options => options_from_collection_for_select(@vendors, 'id', 'name', @job.vendor_id)) %>

you could also use this to display an icon to click on to display the drop-down box by passing an image_tag as the third parameter.