Can't enable Media Sharing in 19.10

[pablosquared]

Hi all,
I find myself unable to enable the Media Sharing function in Ubuntu 19.10. See attached - clicking on the settings option doesn't do anything, no pop modal dialogue that would allow me to enable the function, no option to select folders for sharing.

The system was upgraded from 19.04, and all the way back from 15.10 before that, that may or may not be relevant. GNOME version 3.34.1

Anyone able to help, propose diagnostic steps etc?

[deadflowr]

Click over the dot to the right of the word sharing in the titlebar.
Your theme does you no service.
Is that the yaru dark theme? It's hard to see the button.
Anyway, it's toggled to off.
Once that's enabled the rest open up.

[pablosquared]

Hahah! That was it! Jeez, the Yaru theme made it impossible to see the dot without 1000x zoom on my trusty electron microscope.

Thanks, deadflowr. I'll draw a (light coloured) veil over my dumbness..