Catalina vs Appication Window Screen Sharing

Using Mac running Catalina.
Tried various browsers, including the Jitsi desktop app.
When I try to screen share, and choose ‘application window’, I dont see my other windows as options.
(when I use Chrome, I do see the application windows as selectable, but if I try to share one, the sharing Fails)
I know there are security settings in the Mac’s Setting Preferences, including a ‘screen sharing’ enable toggle. I’ve tried that and other combos of toggles. Nothing working. Anyone know the secret formula to getting this to work?