On CoolTerm noticed that two quick Ctrl-Z can cause it to do a "send".
It pops up a progress bar, and seems to send back out recently received data, possibly some kind of Loopback test?
Same on CoolTerm V146 and V147, using Win10.
Ctrl-Z is grayed out on edit menu, so I'm not sure what ^Z^Z is actually intended to do.
Bug or feature?