Is there a limit on adding staves?

I'm trying to write directly into a score at present, and I seem to have hit a limit on the number of instruments/staves I can create - currently looks like 14. I'm sure I've seen other scores with more instruments, so I'm wondering whether this is a feature of my system or not. I'm using Macos Catalina 10.15. with Musescore 3.5.2 - see below:

OS: macOS 10.15, Arch.: x86_64, MuseScore version (64-bit): 3.5.2.312126096, revision: 465e7b6