The API only accepts resource mapping IDs in the 'pve-configid' format, but the name field of the PCI, USB and directory mapping windows takes any value. A name like 'gpu@node1' is thus only rejected after submitting, with a generic "invalid configuration ID" error that does not tell which characters are allowed. Use the existing 'ConfigId' vtype, so the field is marked invalid right away and its tooltip lists the allowed characters. Signed-off-by: Michal Fox <me@dualfroz.com> Link: https://lore.proxmox.com/20260929141313.2873638-1-me@dualfroz.com