Mixer, can't play all the voices simultaneously?

In Musescore 2, even in ver 3, you can just click anywhere in the staff then you will hear all the instruments and voice parts together, in this new version, you click the piano part staff then you'll hear only the piano, if you click soprano, then it will only play the soprano part, I want to hear all the parts so that I can correct some notes but I can't, I can hear all the parts if I click from the start of the piece but not in any part of the piece. This is very frustrating. I wish I hadn't installed this ver 4, coz now I'm having a problem with the playback, I need to redo the piece again so that I can do it with ver 3, and uninstall the ver 4.