It seems to me (and what do I know?) that considering the isolation of a module, that "xincludefile" should work to include a file that was previously included elsewhere in the program... Since the code in the file is unavailable to the code inside the module. Yes, I know I can use includefile, but it seems that the isolation aspect would justify xincludefile to work in a module for a file not previously included in that module...
Minor, I know.