title: Get manually opened firefox window with Selenium and python
body: <p>As I was working on my Selenium project, I wondered if it was possible to link my project to an already existing firefox window, opened by hand, so not controlled by the marionette.</p>
  <p>I defined a <code>browser</code> as a <code>selenium.Firefox()</code>, and tried to print the <code>browser.window_handles</code>, but it only returned me the window opened by selenium.</p>
  <p>Is there any way to connect to an already existing window ? It would be useful, for example, for a password manager if you don't want to store your logins into your browser, as it is not safe...</p>