Capella

Hello everyone,
I have a question with regards to the use of Library projects in Capella (I’m using v1.3.0 on a Windows . I was working on a project, and then I thought that it would a good idea to have some of the model elements in a library, so that I could reuse them in other projects. I created a Library project and copy-pasted those elements (in particular, Physical architecture). They showed up automatically on all the other projects that reference that library, on the Project Explorer. However, if I create a PAB in one of those projects and try to drag-drop those PCs from the Library, they don’t appear on the diagram. Is it a bug, or am I using libraries in the wrong way?
I was wondering also about the use of REC/RPL in libraries. Should all library elements be RECs, and then just add a RPL on those projects that reference them? Or is it fine to use directly elements of the library, without the REC/RPL feature?
Best regards,