This is a nice program with a good concept. I like the clean appearance and the fact that it avoids GTK and Qt.

There are a couple of things that would improve usability when using large numbers of audio ports and JACK clients however:

1 - Add a fixed display of the matrix crosspoint text, eg. in a toolbar. I use RME MADI cards, and the matrices for the system audio ports are too tall to fit on the screen. When making connections near the top, the text that appears below the matrix on mouse hover isn't visible. An additional fixed position display of that text would solve the problem.

2 - Toggle visibility of matrices on a per-client basis, to reduce clutter when using a lot of JACK clients.