title: window.open(url, windowname, opts) opens in new tab instead of new window in Firefox
body: <p>Seems that (try at <a href="http://jsfiddle.net/9kqp5/" rel="nofollow noreferrer">jsfiddle</a>)</p>
  
  <pre><code>window.open('http://www.google.com/', window_name, 'width=400,height=320');
  </code></pre>
  
  <p>completely stops opening new window in Firefox, whatever you put as window_name (_blank, whatever..)! This must have worked recently (year ago), but now it stopped working! It must be some quite new change in Firefox in the past, also <a href="https://stackoverflow.com/questions/726761/javascript-open-in-a-new-window-not-tab">answers to this question</a> prove this - they worked before but don't work any more!</p>
  
  <p>My suspicion is that it stopped working because the option <code>"Open new windows in new tab instead"</code> (Tools / Options / Tabs) is now true by default! It must be a recent change.</p>
  
  <p>My use case really needs to open just a small simple window with legend - opening new tab for this is overkill.</p>
  
  <p><em>The problem is that it is a default and normal users are not aware of this setting - they just see that the website behaves strange!</em></p>
  
  <p>Is there any way to override Firefox behaviour?</p>