title: Can't upgrade Firefox with selenium
body: <p>Temporarily I upgrade my sofware for automation web test. </p>
  
  <p>I had Selenium 2.41 and Firefox27 working fine. When I try to upgrade the software, there is no problem about Selenium (I can upgrade to the latest release 2.45 and it's working fine with Firefox27) but I can't upgrade to any Firefox version higher than 29...and this is a problem for us. </p>
  
  <p>I tried to run my test but I get this exception at some point: 
  "Failed to start new browser session, shutdown browser and clear all session data
  org.openqa.selenium.server.RemoteCommandException: timed out waiting for window 'null' to appear"</p>
  
  <p>Any idea?</p>
  
  <p>Best regards and thanks</p>