If you say M-x vm-visit-folder RET and then specify an rcp file name, and then change something, and then try to save (with `S'?), you ought to stumble across a bug. Apparently, rcp.el is not invoked for saving the buffer, instead, ange-ftp asks its infamous message about a password for the host `r' or something. Are any of you using VM? Could you try this, please, to help me investigate? Thanks a lot, kai -- Life is hard and then you die.
