Mutliple files open

In MuseScore 3, you could open multiple documents in the same file under it's own tab. Now in MuseScore 4, all files open in their independent window. It was so much easier to copy between tabbed files than having to go from one document to another from separate windows. Can you open multiple files in the same document?

I am not talking about document view - side-by-side.

Thanks,
Terry