I have set "z" key twice on my keyboard in Music Maker. Before i had "y" instead "z" but in one patch it change. I thought I could work with it but it's too annoying.
I forgot to write, I'm apologise. My version of Music Maker is 28.0.2.47. Moreover i notice that "y" don't works on keyboard but already works in MIDI editor. But still it's uncomfortable to work.