Library manager library still not seen after install

I’m new to PIO…

I imported an ESP32 project from the Arduino environment. I added the include for the Arduino and saved it as a .cpp.

The (now) .cpp file has an include for PUbSubClient.h.

I used the library manager to install the PubSuClient library and it now is in:


But, I still get cannot open source file “PubSubClient.h”

So, what did I do wrong? …And how do I fix it?

Could you provide a simple project to reproduce this issue?