I needed a bit more modern version of the good old Buzz sequence editor and ended up with this:
Thanks goes to the master himself because this is 99% based on the horizontal sequence editor you can find in Buzz already. What I did was to switch rows and columns, and did some small tinkering here and there.
Include this to your song and you are good to go. The neat thing is that you can reposition the sequence window next to main Buzz window or separate monitor.
In terms of features it is in parity with the horizontal one. I'm happy with the features so I'm not going to add anything extra. If you are looking for a project that helps you survive the next social distancing period then this might be it

Enjoy.