Firebug is not displaying in Firefox 31.0
<p>Firebug 2.0 is installed and is enabled for Firefox 31.0, but I am unable to see the Firebug icon within the browser toolbar.
For cross checking I have pressed <kbd>F12</kbd> to launch Firebug, but it doesn't work either.
I have tried with reinstalling the Firefox 31.0 as well as Firebug.</p>

<p>I can't upgrade it to Firefox 36.0.</p>