[NewsFox] the news' title: left-clicking vs middle-clicking

[myrdd]

This bug has originally been mentioned in #18 (comment).

Steps to reproduce & what happens:

1. Install RequestPolicy and NewsFox, set RequestPolicy's default policy to "deny".
2. Open NewsFox
3. Open a news feed (left pane) and select a news (upper right pane).
4. Left click on the news' title (lower right pane), see image:
   • 
   • what happens?
   • A redirection bar appears. It should not. There's no redirection.
   • 
     • Additionally, in the "add rule" menu, there's an „Allow requests from newsfox to *.mozdev.org“ entry. The origin host „newsfox“ makes no sense in this case. Still, it's correct – the URI of the NewsFox tab is chrome://newsfox/content/newsfox.xul.
     • Screenshot:
     • 
5. Middle click on the same link as in (4)
   • The news page opens in a new tab in the background, without any redirection bar. So this works as expected.
6. Again left click on the same link as in (4)
   • The news page opens in a new tab, in the foreground. So now, after middle-clicking, also left-clicking works!

What should happen?
There should be no redirection bar in step (4).