Hey @looplex,
1, you are right if you have the Rights like this:
[image: 1655977697352-430b32a5-1d9b-480b-9741-2baa9ce3d1f6-image.png]
It should be possible to see all categories on the overview Page of all objects which are Clients.
In order that these limitations take also effect in the object browser, in the location view as well as in the CMDB Explorer, you have to define advanced settings under Administration → System settings → Expert settings:
auth.use-in-cmdb-explorer 1
auth.use-in-object-browser 1
auth.use-in-location-tree 1
You can find a detailed explanation of these settings in the article CMDB (User Rights Management).