Uaaah, the obvious thing.

You are correct, every returned input has '\cM' appended, with the obvious exception of the menues.

Thank You. Now I have a hint to continue.

Edit:

Looking at the code, the regex "/\A\R\z/" is used to identify the return key. Of course, this matches '\r'. Afterwards exactly this character is appended to the input and spoils enter-handling.

As a quick hack, I modified Prompter.pm, line 1379, the following way:

# Add newline to the accumulated input string...
#$input .= $next;
$input .= "\n";
[download]

This seems to help me, but is a hack