If I don't specify a thornlist on the command line of "sim build", the thornlist is taken from the etc database, even if there is a stored thornlist in the existing configuration. I don't know the best solution to this problem, but I don't want to have to keep typing the thornlist every time I build, when it is not something that changes frequently. Maybe a solution is to do something different when building a configuration for the first time. If the configuration doesn't exist, use the thornlist from the etc database, overridden by the command line option if present. If the configuration does exist, use the thornlist from the configuration, unless the option --update-thornlist is provided, in which case the "new configuration" behaviour results. We could add a warning to users who specify --thornlist on the command line for an existing configuration without specifying --update-thornlist. This needs some thought.