When dealing with support issues, it is surprising that some developers are unaware of FGLDIR/demo. When we refer to FGLDIR/demo we are referring to the demo programs that are shipped with the product in $FGLDIR/demo. (For Windows users read that as %FGLDIR%\demo).
These have been there since the products inception, and before looking at the age of some of the sample programs!
If you have not seen these FGLDIR/demo programs, I would encourage you to have a look around and get familiar with some of them as they are a valuable tool from which you can experiment and learn.
They are also a valuable tool with support issues, particularly when you are having trouble breaking a program down to a minimal reproducible example.
You can read more at
https://4js.com/ask-reuben/ig-73/ Reuben