No sound alerts

X-N v. 4.0.1 is not producing any sound for alerts (FF 49.0.2).  I have tried changing the sound file in settings, but to no avail.  All other audio on FF and on my machine are working fine.

Additionally, the alert pop-up only stays visible for a couple seconds, vs. ~5-10 sec. in the old version.  Any way to make it longer?

Thanks!