PyCharm 2018.1.4 Professional: Open port per project

I am a PyCharm community user. At the weekend I looked at PyCharm Professional with a colleague on his laptop. Really interesting.

But I have a question about the open ports. Why is one port open per open project? This is not the case in the community version. Here are some examples with 4 | 2 | 1 open projects:

PORT      STATE SERVICE
41243/tcp open  unknown
43105/tcp open  unknown
43841/tcp open  unknown
44367/tcp open  unknown

PORT      STATE SERVICE
35865/tcp open  unknown
44345/tcp open  unknown

PORT      STATE SERVICE
35865/tcp open  unknown

The laptop runs on Linux and the ports are only open when Pycharm Pro is running.