My keyboard volume keys up and down are working. But I did nothing about this in i3. I think this is related to the system. About my status bar when I click on

My keyboard volume keys up and down are working. But I did nothing about this in i3. I think this is related to the system. About my status bar when I click on the volume, I open "alsamixer" in a terminal. I also have, wifi, network, dropbox as tray icons. Wifi and Lan icons come from the package networkmanager.