Disconnecting a port doesn't free the network point.
Behaviour have change from 0.71 to 0.72 in makeConnector / removeConnector
Logical informations (IP, ...) are no more copied/clean, it seems ok.
Physical information (netpoint) should be copied/clean as in 0.71.
It is very difficult to manage the port / netpoint attachement as an used port cannot be reassigned.