No longer be able to change the notification sound !

[valley_nomad]

I found that I am no longer able to change (including mute) the sound for notification. It is always on and plays the same tone I set at the very first time :-( Does any one have the same issue?
My HTC One is an original US unlocked 32GB version with 1.29.1540.16 software.

 

[valley_nomad]

I fixed it ;-)

What happened was I use Yahoo email app which sets its own notification sound and overrides the sound control set via Settings.