Install gnome-shell-extension-better-volume by entering the following commands in the terminal:
sudo apt update sudo apt install gnome-shell-extension-better-volume
Description:
GNOME Shell extension that improves volume control
This simple extension implements two small features: . When using the mouse-scroll over the volume indicator, the volume slider appears and displays the appropriate level. . Clicking on the volume indicator using the mouse middle button will toggle output mute.
Homepage: https://github.com/Tudmotu/gnome-shell-extension-bettervolume
Version: 0.0-git20170425.1a66fab-1
Section: universe/gnome