I just took the submit button off my high score screen, I was having too much trouble with the button.
I did it with the Keyboard object.
Keyboard Return is down
System Trigger Once
In the event, it reads whatever is in the text field. So you would know the next character in the box was a Return Key.
I added the "System trigger once" so it wouldn't submit more than one time.
Is that what you mean, or at least offer an idea?