It's the Dynamics control as previously said.
It allows soft and louder expression which can be useful to play with feeling .
I am experimenting with It at the moment
Switch dynamic control off and everything stays at the same level.
It's not old bug bug!!
There is a lot of nuances to explore. like frequency ranges of how instruments sound which can be adjusted.
The arpeggios are great for filling out songs, but that could be intregrated in a style.
Lots of delving to do.
In a couple of months i will put some music up, but I am still learning the Genos and Cubase.
ATB
John