Did you try to Restore Defaults? Because it does more than reset the sidebar (that’s just the most visible change), and is a common solution to, “my collections tab shows everything”, and has worked for me in the past:
- Collections tab not showing collections, just all movies - Plex Players / Desktop Players - Plex Forum
- Collections tab showing library, not collections - Plex Media Server - Plex Forum
- Collections tab showing Library, not Collections - Plex Media Server - Plex Forum
- Collections showing entire Library - #6 by gordonjb
