The option to select “Visible On” for collections seems to be missing and no longer available. I have tried using Plex Web https://app.plex.tv/, my direct server url, and the Plex Desktop app. I have restarted my server multiple times, and it still will not show up.
The Visible on context menu is showing up fine for me in all cases.
Do you get the same result on different browsers? Can you test disabling any browser add-ons / extensions / plug-ins that might interfere with how a page is displayed? Maybe one of those is messing up this entry (in case you have any).