Resources are not shown

Hello, I currently have the problem in 21x that I can't see any resources in the main view, for example when I switch from the app "Manufactured Item Definition" to the app" Factory Flow Simulation" or "Plant Layout Design".

If I first open the "Plant Layout Design" app with no content, and then search for my PPR context, it opens in a separate tab and everything displays normally.

Do you know why I no longer see my resources right away?