Thank you for reporting this issue and helping to make Ubuntu better!
I've tried to reproduce your problem following this steps: 1) Opened firefox 2) Clicked Edit menu 3) Tried to raise volume with shortcuts
It didn't work as you have described in your report.
I'm going to move this report to gnome-control-center although I'm not sure that this is the appropriate place.
Thank you for reporting this issue and helping to make Ubuntu better!
I've tried to reproduce your problem following this steps:
1) Opened firefox
2) Clicked Edit menu
3) Tried to raise volume with shortcuts
It didn't work as you have described in your report.
I'm going to move this report to gnome-control- center although I'm not sure that this is the appropriate place.