title: Selenium 3.4.0 with Firefox 55
body: <p>yesterday my Firefox browser updated to 55. Since then my code wont work any more. Im using Selenium 3.4  geckodriver 18.0 and Firefox 55. In chrome it works. i got the following message: </p>
  
  <pre><code>&gt; 1503585931231 geckodriver INFO    geckodriver 0.18.0
  &gt; 1503585931265 geckodriver INFO    Listening on 127.0.0.1:31895
  &gt; 1503585932805 geckodriver::marionette INFO    Starting browser C:\Program
  &gt; Files\Mozilla Firefox\firefox.exe with args ["-marionette"]
  &gt; 1503585936703 Marionette  INFO    Enabled via --marionette Unable to read
  &gt; VR Path Registry from
  &gt; C:\Users\Ja\AppData\Local\openvr\openvrpaths.vrpath [GPU 2512]
  &gt; WARNING: pipe error: 109: file
  &gt; c:/builds/moz2_slave/m-rel-w64-00000000000000000000/build/src/ipc/chromium/src/chrome/common/ipc_channel_win.cc,
  &gt; line 346 1503585942553    Marionette  INFO    Listening on port 49243
  &gt; 1503585943132 Marionette  INFO    Listening on port 49243
  &gt; 1503585943228 Marionette  DEBUG   loaded listener.js Aug 24, 2017 4:45:43
  &gt; PM org.openqa.selenium.remote.ProtocolHandshake createSession
  &gt; INFORMATION: Detected dialect: W3C
  &gt; 1503585944268 Marionette  DEBUG   Received DOM event "beforeunload" for
  &gt; "about:blank" 1503585945049   Marionette  DEBUG   Received DOM event
  &gt; "pagehide" for "about:blank" 1503585945051    Marionette  DEBUG   Received
  &gt; DOM event "unload" for "about:blank"
  &gt; 1503585945102 Marionette  DEBUG   Received DOM event "DOMContentLoaded"
  &gt; for "http://www.phptravels.net/"
  &gt; 1503585945208 Marionette  DEBUG   Received DOM event "pageshow" for
  &gt; "http://www.phptravels.net/" 1503585970177    Marionette  INFO    New
  &gt; connections will no longer be accepted Aug 24, 2017 4:46:13 PM
  &gt; org.openqa.selenium.os.UnixProcess destroy SCHWERWIEGEND: Unable to
  &gt; kill process with PID 11736
  </code></pre>
  
  <p>Has somebody the same problem and maybe a solution? or should I just downgrade Firefox? </p>
  
  <p>Forget to say that iam working with Selenium WebDriver.</p>
  
  <p>Thanks for answering.</p>