MATLAB: The FileName property of a figure is not empty

MATLAB

I am not working with GUIDE yet find the full path of the file as the FileName property
instead of an empty string as documented in the "Figure Properties" (MATLAB R2015b):
    "If you are not working in GUIDE, then the FileName property is empty."
Why this is happening?

Best Answer

This is a documentation bug.
There are no workarounds.