FGL_WINMESSAGE and FGL_WINQUESTION are not built-into the runtime system, but are examples of utility functions that we provide. As such if you look in $FGLDIR/src/fgldialog.4gl you will find that these functions are implemented by 4gl code and are compiled into $FGLDIR/lib/fgldialog.42m
This means that if you are not happy with these utility functions, you can look at the source and use these as inspiration to write your own library functions.
Read more at
https://4js.com/ask-reuben/ig-39/
