I'm sorry: I am connected to my debian system via ssh, but now the auto-multiple-choice GUI appears on the gnome desktop on that computer, and not on the system which hosts the ssh terminal. How could I redirect the GUI where I want it? I always started auto-multiple-choice in a terminal connected via ssh, but now it doesn't work anymore.

use ssh -X ?

Yes, I have tried with ssh -X and ssh -Y: the other program works, but auto-multiple-choice don't.

That's strange: it works with my setup and ssh -X.

It worked on my system too. After an upgrade, it stopped. I don't know where to look: is it a perl problem? An ssh problem (seems not, as all other programs work fine)?

I solved my problem: someone told me that the new debian release uses Wayland instead of X, and that's probably the cause. If I close the graphical session on the host machine, then I can redirect everything via ssh, using ssh -X or ssh -Y. If there is an active graphical section on the host machine, then the auto-multiple-choice GUI appears on the host, and not on the client. I don't know if this is a bug or a feature of Wayland.

Thanks for the update and solution!