title: Rails 3.1 with Asset Pipeline, link_to :confirm message showing twice?
body: <p>Okay, so I've seen <a href="https://stackoverflow.com/questions/4475449/link-to-confirm-displays-popup-twice">this question</a> about this problem being caused by multiple linkings of jQuery or Prototype, but I can confirm that I'm only linking to jQuery <em>once</em> on the entire page. My problem is this: when I have a <code>link_to</code> that confirms a deletion, the popup shows twice. Here's the applicable code in my template (written in Slim):</p>
  
  <pre><code>link_to('Destroy', depot_path(@depot.id), :confirm =&gt; "Really?", :method =&gt; :delete)
  </code></pre>
  
  <p>I'm running <strong>Rails 3.1.0</strong> with the Asset Pipeline turned on, with <code>gem 'jquery-rails'</code> in my <code>Gemfile</code>, and the following is in my <code>application.js</code> file (which is compiled by Sprockets for the asset pipeline).</p>
  
  <pre><code>//= require jquery
  //= require jquery_ujs
  //= require 'underscore'
  //= require 'backbone' 
  </code></pre>
  
  <p>I have <code>underscore.js</code> and <code>backbone.js</code> in my <code>/vendor/assets/javascripts/</code> directory, and sprockets seems to find those okay. I've also searched through the <code>application.js</code> file that sprockets serves up, and jQuery is only in there once, and jQuery UJS is only in there once. This is what my head looks like when my page renders (I've omitted the <code>csrf-token</code> value for display, FWIW).</p>
  
  <pre><code>&lt;head&gt;
    &lt;meta content="text/html; charset=utf-8" http-equiv="content-type"&gt;
    &lt;title&gt;Administration&lt;/title&gt;
    &lt;link href="/assets/screen.css" media="screen" rel="stylesheet" type="text/css" /&gt;
    &lt;script src="/assets/application.js" type="text/javascript"&gt;&lt;/script&gt;
    &lt;meta content="authenticity_token" name="csrf-param" /&gt;
    &lt;meta content="--token--omitted--" name="csrf-token" /&gt;
    &lt;script src="/assets/common/subdata.js" type="text/javascript"&gt;&lt;/script&gt;
    &lt;link href="/assets/show.css" media="screen" rel="stylesheet" type="text/css" /&gt;
  &lt;/head&gt;
  </code></pre>
  
  <p><code>subdata.js</code> has some Backbone-specific code in it; nothing that would choose to include jQuery again. So what's the deal? I don't have an additional jQuery file anywhere in my project; it's all managed through the <code>jquery-rails</code> gem. What's causing my <code>:confirm</code> method to fire twice?</p>
  
  <p><strong>EDIT</strong>: I was previously seeing this on RC5 of Rails 3.1, but now I'm also seeing it on Rails 3.1 actual.</p>