can you add some sound to notifications?

Useful application. The only real thing keeping me from giving a full 5-stars is that I want the ability to NOT show notifications on pages that are currently active.

For example, a mail website. The title bar might say "5 unread", but once I read one email, the title changes to "4 unread" at which point I get a notification on my desktop. I want the ability to either not show that via settings or as a permanent change.

This extension would be very useful if it works well - and if can be customized for the sites/pages I would only want to be notified .
I installed it and it does not work in my FF 50.1.0 win8.1:
1. I do not see any options/setings like in the older version.
2. I do not see any messages
3. I do not see any icon - maybe I am not supposed to...
4. there is no parameter tabnotifier in about:config
I re-installed it a couple of times - same ;-(
I see it works for others...what do I have wrong?
UPDATE:
After re-install 3rd time I get messages - BUT I have:
NO add-on icon, NO disable button on the message (so I cannot disable a page notifing me) and NO options to change (in add-on page). What is it wrong? I use NoScript - does it interfere?
Thank for any help!

Yes, it's working again but the problem is in my version of Firefox (49.0.1 on Linux Ubuntu) the corner icon to suppress further notifications doesn't appear.