I find that setting another key to the UI > Escape command does work as expected, but it’s important to realise that the Esc key has several purposes in Dorico. For example, if the caret is shown and you hit Esc, it’s actually the Note Input > Stop Note Input command that is executed. And when you are in a dialog and you hit Esc, that isn’t triggering a command in Dorico at all, but rather it’s being handled by the dialog itself, and you cannot specify a key command to cancel a dialog in that way.