Unresolved reference - sources root not working

Attemping to set a source root within Pycharm. It's not seeing the modules in the specified source folder.

As you can see from the attached, the ibapi directory is set as a sources root. The files are present, yet the import statements are throwing an Unresolved reference error.

I am able to resolve this by actually installing the ibapi package (through the blue link below, or Python Interpreter menu).

However, this is irritating me; because I want to use and modify the classes locally.

Can anyone shed some light? Everything seems to be in order. Thx, Keith :^)