Select2 selection box

I have a formatting problem with the following function. As you will see below, it mostly works, it's just that the search box formatting is not what I want (I want to replicate a Twitter-like Bootstrap function):

The user can enter the title of the book in the search box, get a selection of books to select from (via ajax) in the dropdown under the search box, and select the book. After selecting a book from the drop-down list, the form is filled with information about the book. Same:

My problem is that select2 automatically changes the format of the input search (adds css around the selected item in the search box). See here:

Question

I know this is not exactly what Select2 needs to be used for, but I would like the search field value to be "rails", which is similar to how it was when I typed it in (first screenshot). How do I keep the standard input format?

Details:

Here is the coffeescript code I have so far (it has asynchronous image loading and highlight formatting):

jQuery ->

  get_image = (unique_id, image_url) ->
    img = $("<img  />").load(->
      $(".#{unique_id} .typeahead_photo_wrapper").html(img)
    ).error(->
      $(".#{unique_id} .typeahead_photo_wrapper").html("No preview")
    ).addClass('typeahead_photo').attr({src: image_url}).fadeIn(500)


  format_item = (book) ->
    console.log book
    itm = ''
    itm += "<div class='typeahead_wrapper #{book.isbn}'>"
    itm += "<div class='typeahead_photo_wrapper'>"
    itm += "<div class='typeahead_photo'>...</div>"
    itm += "</div>"
    itm += "<div class='typeahead_labels'>"
    itm += "<div class='typeahead_primary'>#{book.title}</div>"
    itm += "<div class='typeahead_secondary'>#{book.author}</div>"
    itm += "</div>"
    itm += "</div>"

    get_image(book.isbn, book.image)
    itm


  update_with_item = (item) ->
    keywords = $("#learning_item_book_search").val()
    # console.log item

    $("#new-book #learning_item_unique_identifier").val(item.isbn)
    $("#new-book #learning_item_source").val(item.source)
    $("#new-book #learning_item_name").val(item.title)
    $("#new-book #learning_item_description").val(item.description)
    $("#new-book button").focus()
    item.title



  retrieve_books = (data) ->
    books = []
    $.each data, (i, item) ->
      books.push(
        id: item.id
        isbn: item.isbn
        title: item.title
        author: item.authors
        description: item.description
        image: item.volume_info.imageLinks.smallThumbnail
      )
    books


  $("#learning_item_book_search").select2({
    minimumInputLength: 2
    tags: true
    ajax:
      url: "/raw_items/fetch_books"
      dataType: 'json'
      quietMillis: 200
      data: (term, page) ->
        query: term
      results: (data, page) ->
        return {results: retrieve_books(data)}
    maximumSelectionSize:1
    formatResult: format_item
    formatSelection: update_with_item
    formatInputTooShort: (term, minLength) ->
      "Searching book on Google books"
    dropdownCssClass: 'typeahead'
  })