Thank you very much. That seem's to be the solution. Step edit only works for parts of self recorded styles, but not for Yamaha styles. There are locked. I never tried to to this on the S970.
No, it is not true. What are you telling me here means you neverbuild CASM section for styles for different type of chords. Yamaha style concept are build on 16 channels, but only 8 (as other brands has too) in front of user. If you build a complex style, with more than 8 channels, you cannot step edit or even activate that channel for recording, without deleting the events bond to that channel. For example, if you record a bass channel which on M/m will do a sequence of notes, but you want for 7th or dim7 to get other sequence of notes, you have to build this style in a soft, Yamaha style creator is very poor soft, and you have to use pc soft to do that. Yamaha do often this technique in styles, and those styles which have more than one channel bond one to other by CASM section, you cannot edit in keyboard.
I do this for at least 10 years, or long time