title: Can't open DevTools on NW 0.13 in Linux
body: <p>Since NW 0.13 I cannot open the devtools anymore.</p>
  
  <p>According to offical <a href="http://docs.nwjs.io/en/latest/For%20Users/Migration/From%200.12%20to%200.13/" rel="nofollow">documentation</a>, it should be possible to open the DevTools in Linux by pressing <code>F12</code>.</p>
  
  <p>I've tried <code>F12</code>, <code>ctrl+shift+J</code>, <code>ctrl+shift+I</code> but none of them is working. Is it a bug or am I doing wrong?</p>
  
  <p>I'm on Gnome shell 3.20.2 and NW is 0.13.4</p>