Hello @RichardDL,
It works in either folder for me.
I was meticulous testing these seperately.
Here is a tidbit for you:
println(dataFile(""));
println(dataPath(""));
println(dataFile("").getAbsolutePath()); //See the source on GitHub
println(sketchFile(""));
println(sketchPath(""));
I found those in the source here:
https://github.com/processing/processing/blob/master/core/src/processing/core/PApplet.java
:)