Armagnac,
As for your first question: always two systems (violin and bass keys) are displayed in the notation view, even if you only need one system for your melody. To my knowledge this cannot be switched off, you can only select which system to print when printing the notes.
It would by a nice feature to switch on/off unneeded systems also in the notationview.


Biab/RB latest build, German Language Pak, Win 10/64 Pro, 1 TB SSD, 32 GB RAM. Notation SW Finale, StaffPad, SmartsScore – Playing Double Bass, Guitar, Piano