I think this is probably because the positions on the mountpoint, not the files in the volume, were still set to root:root. Can you please confirm that the permissions on /media/usbdisk-1 are working?
-- Ubuntu doesn't show correct owner/permissions on removable drive https://launchpad.net/bugs/47962 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
