How to mute a scale on chord track when clicking

is there a way to mute a scale on chord track when clicking?
I did mute an entire chord track but scale is audible when clicking them in piano roll

Sorry not at Cubase so this response is a bit generic.

If you mean you want to Mute an actual Chord Event, all you need to do is Select the Mute Tool and click on the Event.

If you mean it is producing a sound whenever you click on it, then there is an Acoustic Feedback feature in the Key Editor which can be turned on & off. I always leave this off so I don’t know its proper name - I think there might be a Toolbar button.