title: Get focus on the new window in Selenium Webdriver and Python
body: <p>Using Selenium Webdriver in Python I am able to click on a button that opens a new browser window, but I have no idea how to change the focus onto the new window. I've searched all over the internet, but found nothing helpful.
  The problem is that the window doesn't have a title!</p>
  
  <p>What I need is the focus on the new window, so I can take a screenshot of its contents.</p>
  
  <p>Here is the bit of code around the button that opens the new window:</p>
  
  <p><img src="https://i.stack.imgur.com/eLUh7.png" alt="enter image description here"></p>
  
  <p>How to do that...?</p>