hello Antoine, I have got a reply from xdg from a user who has the same problem: https://lists.freedesktop.org/archives/xdg/2018-April/014010.html
So it looks like this might be a GNOME(3) problem (or can you reproduce this with KDE or another desktop?) I think it would make sense to report this against GNOME (either upstream or in Debian), unless you can reproduce it with KDE, e17, etc. Cheers and Best Regards, -- Felix Natter debian/rules!
