When microphone is used, the microphone icon appears is System Tray, so normally/simply if I want to change microphone level I should left click by mouse on microphone icon then be able to change its level, but what we have is that the microphone icon serves only as indicator that says the microphone is currently used and we can also mute it by right click menu. So in order to change microphone level I should go to speaker icon and click on it then change the microphone level, thankfully mouse scroll works on the microphone icon. What I think should be the normal behavior to have the left click by mouse on microphone icon opens the same widget that appear when we left click by mouse on speaker icon, so like this the icon role become logical and intuitive to users.
Created attachment 131222 [details] microphone icon
The best way to approach this case by putting together both speaker and microphone icons under one block like what attached image shows. In case where microphone is not used only speaker icon is shown.
That could work, but we don't currently have the ability to use non-square system tray items. We would need to do add that first.