enlightemnent_open is called by xdg-open and xdg-open is meant to open any file base on mime type -= ie a dir will come up in the file manager, a jpeg will use whatever image viewer is known to handle that like you double-click the jpeg in efm ... and thus executables like xterm will be EXECUTED. thats how it's meant to work. enlightenment_open does what would happen if you double-licked on that file icon. so it's doing exactly what it is intended to do.