Hey!
I use a french azerty keyboard and I noticed in the SFX editor that the keyboard key for G# (6) is the same as the hotkey to go back to previous SFX screen (minus).
This means if I want to play G# in SFX 01, pico-8 plays it and then comes back to SFX 00, and I have to go back to SFX 01 to continue playing.
Thanks a lot!

That is not the only hotkey for G#.
You can press the other hotkey for G# (h) and then change the octave in the editor

Thank you for the tip but I hoped for a more convenient resolution. I often play on my piano (using the midi2pico8 tool from @samhocevar) or use G# from octave 1 and G# from octave 2 in the same SFX, so your solution would not be the most comfortable for me.

I also use a azerty keyboard and started a thread where I listed the bugs that make editing music quite painful: https://www.lexaloffle.com/bbs/?tid=37093. It was the 2nd thread I made about those bugs, some years ago, forgot about the 1st one, but none received any reply :( I wish @zep moved the keys he uses for editor shortcuts far from those used to enter notes, or used a modifier like ctrl+key.