Android Question File.DirRootExternal Question

My app creates a folder under File.DirRootExternal when it is first started if that folder doesn't exist. When I use a file manager on the phone, I see the folder along with Download, Movies, Music, DCIM ect. However, when I plug the phone into my PC, I see every folder EXCEPT the one I created.

I'm not sure what I'm doing wrong here but I'm sure somebody has an explanation.

Kurt