how to mute single instruments in note performer?

I’ve just finished an orchestral score with nearly 50 staves. Playback runs with three VST note performer 3 players. The mixer window shows the VST single instruments and I can move the volume sliders. But there is no volume change at all happening to the playback track! Even if I turn down the slider to 0 the sound remains unchanged. I can’t find any mute optiones except the whole VST-player. I need to mute one instrument completely and don’t want to delete it completely too …
Please help me!

Open the NotePerformer Mixer (in Play, under the VST Instruments on the right, click the midde ‘e’ icon) - there you will find Mute and Solo buttons for each instrument…

Thank you, I got it!