title: Google's reCAPTCHA broken when using Selenium
body: <p>I'm trying to automate a process where one page can only be accessed after filling a reCAPTCHA (asking to identify images).</p>
  
  <p>I'm not interested in solving the captcha automatically as it is enough for me to complete the captcha manually and let the other tasks be automated; the only problem is that the captcha widget is broken and exhibits a weird bug in the Firefox window opened by Selenium (while it works fine with my normal Firefox instances) making me unable to complete it, even manually.</p>
  
  <p>The bug: every time I try to select an image it fades out and a new one pops up, taking its place. I'm not able to keep any images selected and can't verify the captcha.</p>
  
  <p>What could cause this behaviour? The two Firefox instances appear identical (same user agent as well) but there must be something different for this to happen. How can I debug this?</p>