Yeah I try to avoid those types of presets.  Those are only CERTAIN presets in Nexus..

They are often identified by:

• SQ
• DL
• (or if they have a BPM identified)

If you use other presets like leads, pianos, guitars, bass, pads, etc.. you’ll be able to play melodies with your MIDI Keyboard with both hands (all the keys).

If you purchase third-party expansions for reFX Nexus, be careful you only buy packs with not many SQ or DL presets, as I don’t find those very useable (and I don’t like the pre-made drum loops because I always teach custom beatmaking here at itsGratuiTous.com!)