The “lock channels” and “set as fallback” icons are missing for me in pavucontrol in 13.1 (see screen-shot).
http://i1252.photobucket.com/albums/hh570/Thailandian/Screenshots/missingpavuctrlicons_zps4073e816.jpg](http://s1252.photobucket.com/user/Thailandian/media/Screenshots/missingpavuctrlicons_zps4073e816.jpg.html)
I did a quick search, and I see that this was a problem in Ubuntu back in 2009 (see https://bugs.launchpad.net/ubuntu/+source/oxygen-icons/+bug/486605) but only for the Oxygen theme. I’ve tried other icon themes - even the Default Gnome Theme - and the icons are still missing.
Is anyone else having this problem?