Signature help will be closed unexpectedly on inputting the 2nd keyword argument.
In this case, the signature help window was closed on inputting the 2nd keyword argument noop for FileUtils.cp:

Inside the InteractionWorker, inputting the 2nd argument will cause SyntaxError because noop is considered a positional argument after the keyword argument.
I got a #<Parser::SyntaxError: unexpected token tRPAREN> exception on parsing on I input the first character of noop.
And it will close the signature help window. It would be better to keep the window even if SyntaxError is raised.
Is sending the latest signature help response better if SyntaxError is raised?