Racer bug?

index.coffee

app = require('derby').createApp(module)
  .use(require 'derby-ui-boot')
  .use(require '../../ui/index.coffee')


# ROUTES #

# Derby routes are rendered on the client and the server
app.get '/', (page) ->
  page.render 'home'

app.enter '/list', (model) ->
  model.on 'change', '_page.item_id', (id) ->
    console.log 'change '+id
    item_query = model.at 'items.' + id
    model.subscribe item_query, (err) ->
      if !err
        item_query.ref '_page.item'
      else
        console.log err

app.get '/list', (page, model, params, next) ->
  # This value is set on the server in the `createUserId` middleware
  userId = model.get '_session.userId'

  # Create a scoped model, which sets the base path for all model methods
  user = model.at 'users.' + userId

  # Create a mongo query that gets the current user's items
  itemsQuery = model.query 'items', {userId}

  # Get the inital data and subscribe to any updates
  model.subscribe user, itemsQuery, (err) ->
    return next err if err

    # Create references that can be used in templates or controller methods
    model.ref '_page.user', user
    itemsQuery.ref '_page.items'

    user.increment 'visits'
    page.render 'list'


# CONTROLLER FUNCTIONS #

app.fn 'list.add', (e, el) ->
  newItem = @model.del '_page.newItem'
  return unless newItem
  newItem.userId = @model.get '_session.userId'
  @model.add 'items', newItem

app.fn 'list.remove', (e) ->
  id = e.get ':item.id'
  @model.del 'items.' + id

list.html

<Body:>
  <div class="row">
    <form class="span3" x-bind="submit: list.add">
      <h3>Add item</h3>
      <fieldset>
        <label>Name</label>
        <input type="text" value={_page.newItem.name}>
        <label>Note</label>
        <textarea>{_page.newItem.note}</textarea>
        <div>
          <button type="submit" class="btn">Add</button>
        </div>
      </fieldset>
      <div class="well visits">
        <b>Fun fact:</b> You've visited the list {_page.user.visits} times.
      </div>
    </form>
    <div class="span8 offset1">
      <table class="table">
        <thead>
          <tr>
            <th>Item</th>
            <th>Note</th>
          </tr>
        </thead>
        <tbody>
          {#each _page.items as :item}
            <tr>
              <td>{{:item.name}}</td>
              <td>{{:item.note}}</td>
              <td><button class="btn" x-bind="click: list.remove">Remove</button></td>
            </tr>
          {/}
        </tbody>
      </table>
      <hr>
      <select>
      <option value="" selected="{equal(_page.item_id, '')}">select item</option>
      {#each _page.items as :item}
        <option value="{:item.id}" selected="{equal(_page.item_id, :item.id)}">{{:item.name}}</option>
      {/}
      </select>
      <h3>selected item</h3>
      <p>{_page.item}</p>
    </div>
  </div>

Modifications

index.coffee
line 12 ->

list.html
line 46 ->