Updated the description a bit. Also here's the proof that MATE still uses GTK+2 version of indicator-sound:
monsta@mate:~$ ps aux | grep indicator-sound monsta 3020 0.0 0.4 552868 13156 ? Sl 14:23 0:00 /usr/lib/indicator-sound-gtk2/indicator-sound-service monsta 3589 0.0 0.0 14772 2124 pts/4 S+ 14:28 0:00 grep --color=auto indicator-sound
Updated the description a bit. Also here's the proof that MATE still uses GTK+2 version of indicator-sound:
monsta@mate:~$ ps aux | grep indicator-sound indicator- sound-gtk2/ indicator- sound-service
monsta 3020 0.0 0.4 552868 13156 ? Sl 14:23 0:00 /usr/lib/
monsta 3589 0.0 0.0 14772 2124 pts/4 S+ 14:28 0:00 grep --color=auto indicator-sound