Connection test to HTTPS defaults to port 80

In my jetty.xml ports 80 for HTTP and 443 for HTTPS are configured as listener ports.
But when I perform a "Test connection" in the partner configuration window for HTTPS-URL "https://localhost/as2/HttpReceiver",
the test fails since the connection is established to port 80 (default for HTTP) instead of port 443 (which should be default for HTTPS).

This is the test result:

[11:05:35 AM] [Connection test to localhost/] A direct IP connection is used
[11:05:35 AM] [Connection test to localhost/] Starting connection check to localhost/ using SSL/TLS connection. Please remember that during this test your client will trust all server certificates and will ignore your TLS keystore - means it is not ensured that your TLS keystore is set up in the right way even if this test is successful.
[11:05:35 AM] [Connection test to localhost/] Setting timeout to 5000ms
[11:05:35 AM] [Connection test to localhost/] Connection to localhost/ established successfully
[11:05:35 AM] [Connection test to localhost/] The found protocol is "NONE", this is not a secured connection. You tried to connect via SSL/TLS to this address but this is not provided by the remote server at this address and port.
[11:05:35 AM] [Connection test to localhost/] Either there is a plain connection expected by your partner, your partner uses the wrong protocol or client authentication is required

The problem is in method testConnection() in class JPanelPartner, I think.
If no port is given explicitly in the URL, the test defaults to port 80 no matter if the URL is HTTP or HTTPS:

URL url = new URL(urlStr);
int port = 80;
if( url.getPort() > 0 ){
port = url.getPort();

I would expect the default port to be 443 for HTTPS-URLs.

Tested in AS2 build 55.