title: Element not found error when using Capybara webkit but the test runs fine in non-headless mode
body: <p>I am trying to run a simple google search test in the headless mode using Capybara-webkit.</p>
  
  <p>I have set the drivers as in env.rb file:</p>
  
  <pre><code>Capybara.default_driver = :webkit
  Capybara.current_driver = :webkit
  Capybara.javascript_driver = :webkit
  </code></pre>
  
  <p>And the feature file has a simple scenario outline which searches for a input and verifies whether the result contains the expected output:</p>
  
  <pre><code>    Given User opens the google page
      When she searches for "&lt;input&gt;"
      Then verify that the result has "&lt;output&gt;"
  
      Examples:
      |input                    | output           |
      |Agile Samurai author name|Jonathan Rasmusson|
      |Eloquent Ruby author name|Russ Olsen        |
  </code></pre>
  
  <p>In the step definition, the google page is visited and the input is entered into the text box and the search button is clicked.</p>
  
  <pre><code>Given /^User opens the google page$/ do
    visit "http://google.com"
  end
  
  When /^she searches for "(.*?)"$/ do |search_query|
          fill_in "gbqfq", :with =&gt; search_query
          click_button "gbqfba"
  end
  
  Then /^verify that the result has "(.*?)"$/ do |output|
          should have_content output
  end
  </code></pre>
  
  <p>When I run these tests, I get the error:</p>
  
  <blockquote>
    <p>Unable to find field "gbqfq" (Capybara::ElementNotFound)</p>
  </blockquote>
  
  <p>But, if I change the driver to selenium:</p>
  
  <pre><code>Capybara.default_driver = :selenium
  Capybara.current_driver = :selenium
  Capybara.javascript_driver = :selenium
  </code></pre>
  
  <p>then, the tests run and all the steps pass.</p>
  
  <p>In the headless mode, are the elements found in some other way?
  Is my approach wrong? I am unable to understand why the element is not found in the headless mode when it works fine in the browser mode (that opens firefox instance).</p>
  
  <p>I am a novice in this field, so any help will be deeply appreciated.
  Thank you in advance.</p>