Thanks for your answer
It all makes sense, but I have a use case where having a buffer spanning multiple monitors is a requirement.
The problem has been emerged when we added support for multiple monitors in Remmina for the RDP protocol. There’s no other way to implement it.
GNOME Connection, vinaigre, wlfreerdp and the like may suffer from the same issue.
Another missing feature is to have a buffer spanning only a limited number of monitors. Today is either one or all.