I think there is something wrong with the protocol options.
I. Please take a look.
1. Setting "SSH/SFTP".

2. Closing the Domain Properties by pressing the OK button.
3. Turning back to the Domain Properties.

("Disable SSL/TLS", "SSL Direct", "Force SSL" and "Disable Mode Z" are not grayed out any more)
4. Then I can set some strange combinations of protocol options.

II. Furthermore...
1. If "SSH/SFTP" is set "HTTPS" is not grayed out. Why?

Because if "HTTPS" is set - "SSH/SFTP" is grayed out.

2. "Disable SSL/TSL" and "Force SSL" can be set. Why?

3. "SSL Direct" and "Force SSL" can be set. Why?

4. If "Disable" is set, I think all other protocol options should be grayed out.
[X] Disable / / Disable SSL/TSL / / SSL Direct / / Force SSL
/ / SSH/SFTP / / Disable Mode Z / / HTTPS
5. Perhaps it would be better to use "SSL/TSL" instead of "Disable SSL/TSL". What do you think about it?
Many thanx for Core FTP Server!

Ron