To save changes made in the Mixer to parameters such as style part volume, the style must be saved from within Style Creator.
Note that the style channel on/off status is not saved with a style.
If you want to incorporate this in a style, the best that you can do is to either delete those style parts that you want to turn off, or more safely, simply set their volumes to zero which will allow you to restore the parts later if you change your mind. Finally save the modified style from within Style Creator.
Alternatively the the style part volumes and channel on/off status can be saved in a registration if the Style group is checked when memorising the reg.
Regards
Ian