it's reading it from the config.properties. you could probably add something to the 'blclient' to strip that entry out so after the client is closed it automatically cleans itself up.
and... submit an enhancment request w/ support to build this in if you can please.
another approach could be to strip out the last entry from the config.properties file then set the file to read only. if the UI can't write to it, it'll perpetually remain blank.