I am currently playing around with using Play Framework on cygwin. I noticed that Typesafe Activator, which has replaced the play command in recent Play versions, ruins the mintty terminal of cygwin: you won’t see any echo of your keystrokes after activator returns.
A simple solution is to blindly type
stty sane into the terminal, which will reset it. Another way is, to wrap the activator in a special cygwin-activator bash script: