Navigation to new window using capybara/selenium gives blank page

demo.feature

Feature: Demo
  Yahoo authentication
  
  @user_login
  Scenario: logging in as user
    Given I am in "http://mail.yahoo.com"
    Then I should see "Sign in to Yahoo!"
    And I fill in userid with "YOUR_USERID" and password "YOUR_PASSWORD"
    And I press "Sign In"
    Then I should be logged in and find "INBOX"
  
  @mail_home
    Scenario: Navigate to Yahoo home page
      When I click on "Yahoo!"
      Then I should see "Mobile" in a new window

demo_steps.rb

steps_for :user_login do
  step "I am in :url" do |url|
    visit url
  end
  
  step "I fill in userid with :userid and password :password" do |userid,password|
    page.fill_in('login', :with => userid)
    page.fill_in('passwd', :with => password)
  end
  
  step "I press :signin" do |signin|
    page.click_button(signin)
  end
  
  step "I should be logged in and find :inbox" do |inbox|
    page.find_link(inbox)
  end
end

steps_for :mail_home do
  use_steps :user_login
  step "I click on :yahoo" do |yahoo|
    page.driver.browser.window_handles.length.should == 1
    page.click_link(yahoo)
    page.driver.browser.window_handles.length.should == 2
  end
  
  step "I should see :mobile in a new window" do |mobile|
    page.driver.browser.switch_to.window(page.driver.browser.window_handles[1])
    page.should have_content(mobile)
  end
end

Test only works if @browser.navigate.to('about:blank') was commented in the reset method of Capybara's driver.rb.