Thanks for this hint, Matt.

I found one: Options, Preferences, Notation, right in the center of that window: Clefs split at.

I didn't find the one with only the bass stave.


Desktop; i7-2600k, 8 GB mem., Win 10 Pro, BIAB 2017; RB 2017 - latest build
Laptop: i5-2410M, 4 GB mem, Win 10 Pro, BIAB 2017; RB 2017 - latest build