Won't show the track volume

I’m using Linux mint 19 and audacity 2.2.1.

When I click on the volume of a track to adjust it , instead of showing me the volume number the audacity screen goes see through where the volume number should be. I can see my desk top picture peeking through. It does the same thing when i click to adjust the panning or the recording level as well.

I think this is due to a known bug in Audacity 2.2.1 (which is fixed in Audacity 2.3.3).

If you double click on the control, do you see a pop-up that allows you to enter a Pan / Gain value?