but a many of your posts are hard to understand because of translation issues.
So I recorded the video.
In the video, you can see and hear that guitar1 has changed in the same style.
I want to know how this changed.
I can't do it.
I looked at the photo you uploaded
https://www.pgmusic.com/forums/ubbthreads.php?ubb=download&Number=20104&filename=2021-12-18_222917.jpgNotice that PartMarker 9d is a different color than the normal blue and green partmarkers. In the instance of your picture of a Chord Chart, the difference of the PartMarker color at bar 9d is the indication of a Style change in the program. (this isn't always the case but it is the case in this instance) If you right click with your mouse on the PartMarker on 9d, the menu that opens will display the style changes.
The markings you made in your picture, the style changes at 9d that you've marked in red display where you can manually change a style in a song without completing all the steps to create a new style and save it as a MultiStyle. This allows you to obtain the benefit of a MultiStyle style change in the working song only. There's no permanent style created and the style change you've input pertains to this one song only.
In this current situation, the style change occurs because there's a style change due to using a MultiStyle rather than a user input manual style change.
Charlie