Playing audio stream not showing in pavucontrol

I got the solution, it was a simple case of the monitor being muted. In pavucontrol go to input devices, then in the show button at the bottom switch it to All input devices. I believe it's normally set to all except monitors, so the monitor doesn't show up. In my case it was this monitor that was muted, but I could still hear sound because the internal audio wasn't muted. Hope it helps someone

Pavucontrol is not configurable other than it saves it's windows dimensions in ~/.config/pavucontrol.ini after program termination to open it with the same size next time. However it usually will increase the windows height adapting to needs when there are more lines to display. Factors which may possibly lead to a wrong windows height may come from larger fonts in our theme.

The only instance I was able to reproduce a missing volume meter was when the windows geometry was smaller than needed:

In this case we can either increase the windows size manually, or we can scroll down the application area to reveal the hidden VU meter:

If this still does not give us a VU meter for reasons unknown to me we may as workaround install and run pavumeter to display the output volume of a playing stream.